I don't think my late parents cheated on one another, but I can't ask them anymore, can't say, But come tell me now this time for real, now that I'm old enough.  As far as I know, they didn't cheat. As far as I know, my mother never cried in a car on the way to her favorite restaurant, like a friend of a friend's mother, who I call the Lorax.  The Lorax's husband told her to get dressed up and pick out the place she wanted to go to, when he had not done so in months, and she spent her fifty-six-year-old day preparing her face, creaming her body, hooking a bra, and doing that thing that women do, touching a part of ourselves we imagine being touched later by a man.  In the car on the way to the favorite restaurant, the Tom Waits song "Shiver Me Timbers" came on.  "I'm leavin' my family / I'm leavin' all my friends / My body's at home / But my heart's in the wind."  Her husband said, Turn it off. Turn it off now.  She said Why, even though she already knew, it was up in her throat like a horse vitamin. She said, If you are about to say something that's going to crush me, then don't take me to my favorite restaurant and do it to me over wine. Pull over, be a man, and do it now.  This story always upsets me. Not because I imagine my parents in these roles. But because I wonder what they'd think if they knew I've been the other woman.  I sat down to write this eighteen different ways. I thought, What does someone want to read about affairs? You've had one and you want to relate to something. You haven't had one but you fantasize about the girl with the keyhole shirt and the shoes your wife would call cheap. Her name starts with a C or a G. You know you and your partner will never have one, but you remember the time your wife, your husband, did not answer the phone for five car-accident hours.  The Lorax has reddish-brown hair and lives in Queens. She's solid and talks a lot.  Every time I meet a married woman, I think about the things she does that likely annoy her husband. I think a great deal about the evanescence of sexuality. The marrow missing from the bone. That's what I want to know. If you're going to wreck some other person's world, what's the good thing you're going to get?  My friend Cobb is from Kentucky. Now he lives in New York, but before he was married to a woman I'll call Blondie. She was hot and perfect-familied, drank a lot, like a college girl. She had a sister, Meg, with dark hair, younger but more mature and sleek. Cobb was happy but not complacent. His wife was both.  After a year or so, Cobb started thinking of dark hair. The swish and wealth of it. On wide southern avenues brunettes jerked his head around. At first not Meg. It was just damn near every brunette. It was forty-five-year-old brunettes at Lancôme counters. It was twenty-seven-year-old cashiers and the dark-skinned Jewish brunettes who perform sure-footed blowjobs on porn sites. Then it was Meg. Then it was the cashier. Then it was both, in his head in the bathroom in the bedroom on a reel billowing like horse manes.  One night at a wine bar, the sisters looked beautiful and disparate. Everybody drank too much and they all went back to Cobb and Blondie's home, and Blondie made it to the bathroom and passed out there, her blond tresses cascading murderously across the tile like southern blood.  As a nation we are obsessed with the moment it happens. When alcohol is involved, the moment is a glance of breath. It's the smell of cologne and lacrosse sweat. Meg is on the bed. Her brother-in-law walks halfway across the room and Meg has this look on her face like pre-sin. A white bra strap is showing.  He kneeled on the bed and she kneeled up to meet him and they kissed and skipped foreplay, pants off, dress hiked up, and they had drilling sex, fast and half-smiling, half look of holy fuck, my sister your wife. The depraved lunacy of gotta have it anyway.  This story doesn't shock me. I see the logic. More than I believe in the sanctity of union and promise, I believe that everybody cheats. If you have not cheated yet, it's because you are still too grateful to be secure, or you have not yet had the opportunity, or the right color of red hair has not come along and sat down at the bar on a Tuesday when the jukebox was playing Leonard Cohen and your manhattan tasted like the future.  Or maybe I'm simply rationalizing and making excuses. Because I relate more to the Lorax's husband than to the Lorax. Because I'd rather be getting fucked in bed than passed out on the bathroom floor.  It's this past summer at a country club in New Jersey where the pool twinkles like 0000. I am reading aloud to a friend from a David Foster Wallace essay in which he talks about how a man who puts his hand at a woman's abdomen while his mouth is between her legs is selfish. Because he wants to know if she comes. He's in it for his ego. Then we talk about cheaters, because I'm telling my friend about a man who was great at that, while he was married. And we talk about the fact that I've been with married men, which I feel taught me to be careful not to get hurt, to know that one day it could happen to me. And she feels it is because I'm worried about losing people, like I lost my parents, so I don't ever put myself in a position to lose. She says I'm just a catalyst for more loss.  We stare across the pool at the families. Dark-haired fathers and blond wives and rows of blond-fur children in Vilebrequin swimsuits.  You shouldn't ever see him again, she says. You're ruining your marriage karma. I say, I'm not sure I believe in it. It's weird you're this fucked-up about marriage, she says. You grew up in a perfect home.  I argue in the general but also in the specific. The fucking moment. The married guy I'm talking about put a cashmere jacket across my shoulders in a downtown bar when the door was open in early spring. I'm happily married, he said in conversation. He had an odd bit of an accent, salt-lick after it's been run through by ten thousand yellow cabs.  Four days later I e-mailed and said I wanted to interview him for a story. I trembled and smiled as I sent it. Six days later we met in a bar far from where he worked and where I lived, but cool and appropriate, and I walked in thinking I was crazy for what I had been thinking, that he was just another married guy, just another finance guy, just another moment in time and scent in a room.  I saw him and I had three beers and I had to run into the bathroom and scream, shriek for fuck's sake. I looked at my face in the mirror and I thought, I have never felt this before. I may never feel this again. Something chemical and explosive. I'll never forget the smell of beer on my breath, that particular evening's smell of beer.  Another bar a few hours later, beer into gin and tonics, side by side on stools, my thigh against his. He says if he weren't married, this would be the best first date he had ever had. He is eight years older. He has a six-month-old baby.  I have to go, he says. I have to go.  He hails me a cab and opens the door for me and I am about to get in, about to be innocent only because he is leading the way, and he puts his hand on my shoulder.  May I kiss you on the mouth? He says it like an apology.  When we saw each other again, he said he didn't want to walk away, that he knew he should but he couldn't.  This time we were in the bar where we'd met, where he knew everyone and he likened me to a jar of cherries beside his glass of Scotch and he kissed me there at the bar and it was the kind that doesn't stop until a full stop. We left together and outside in the street he lifted me into his arms with my legs around his waist and he threw me up against a brick wall. On the way to my apartment a taxi almost hit us and we laughed. He carried me inside and the bottles in my bar stand shook. He threw me on my bed and it was the ideal mix of laughing and panicked desire and he took half my clothes off and his phone rang. We were doing midnight things but across the rest of the city it was 0:00 P.M. and with one hand on my waist, he picked up the phone and said, Yeah honey, don't worry, having a drink with Brian, I'll bring home a pizza.  More than the illicitness of the sexuality, there's a sexuality to the selfishness. To doing precisely what you want to do. Being crudely, smilingly, on the side of the winners. I'm arguing for Wild Moments, because you never know what your last one will be.  She says, I hate myself. She says, This is thrilling.  Call her the Enigma, she works in an office in the center of the city. She's tall and redheaded and thin and in the past she drank a lot and even though she still drinks now, it's different. She's together. She's gotten engaged, it was years in the making. He has a career, the kind that makes the Engima's mother forgive the Enigma's past transgressions. The ring is a holy laurel.  The first morning it's not an affair but a glowing warmth, nobody gets hurt. It begins with an instant message. There's a man in the office who's wildly good-looking, he has great jeans and a hot smile and the other girls and women in the office talk about what he's wearing and how he smells and they trade information like they're handling a rookie card. The Enigma doesn't have the time to, because she is the one he chooses. You look great today, is how it starts.  The Enigma's wearing a white button-down shirt and a dark pencil skirt and her long legs are bare bones in winter and her shoes are popping snake green. Her hair has just been highlighted so it is brighter than yesterday. Everything the Enigma does is done in the extreme  -  it's part of her maddening charm, especially for a man who is in love with her.  In an office, that's how it works, instant messages on the company server. Soon it's eight hours a day, and soon it goes into night. E-mails, because they're quieter than texts. 0:00 A.M. The idea of someone thinking of you, then, who shouldn't be. In bed with his wife. In bed with your fiancé. Nothing has happened, except everything in your head.  I'm losing it, she writes, at 00:00 A.M. on a Tuesday. I'm so scared. I have so much to lose. I'm floored. I'm so scared. I mean, I won't lose it. I'm just addicted.  I say it's like a drug, and the aftermath of a drug is shit. She says, I know I know I know. But. He's amazing. Though. Like. Every moment is erotic. The way he lifts a pen. We are sexy together. You know?  I speak to dozens more people about cheating, so that I can understand the why. So I can understand me.  More than answering the why, women are always asking why. I'm always answering for the men who aren't present. Yes there's the physical, I just want to put it inside her right this second because she's new and her smell is new and her hair isn't blond.  A guidance counselor tells me he cheats because he wants to feel like his old self, the football player who could get it any time. Lana, the woman in the guidance office, won't fuck him until he is no longer married. But he went down on her once, over the covers on a bed that was neither of theirs with her skirt pulled up to her thighs and her panties slid to the right, and then to the left.  I can think of nothing else, he tells me. I have never wanted anybody more. I have wet dreams. Listen to me. I am a cliché.  Dorian, a forty-two-year-old lawyer, says, I don't feel bad because everything had been building toward dissolution at home. And the girl, nineteen, was wearing Express jeans, a blue tank top, her skin was tan and warm, and she was insanely sexual. Her small hands in the creases of his pants. It went from nothing to a lot more than kissing in the back of the black car. The windows steamed up.  What were you thinking, Dorian?  Dorian was thinking, This is so fucking exciting. All of the negative feelings that come with cheating weren't there at the time, he says. The first time there's a strange hand on your pants, Dorian says, I don't know that there's a better feeling on the planet, I don't care who you are or who you're married to.  Dorian got into bed beside his wife that night. He didn't feel badly. He felt justified. You know, he says, the old saying, "Well, if you were taking care of things at home..."  More than guilt, there is fear. You don't want to be found out, he says. Guys who tell you they feel bad, I think it's bullshit. For the most part, you don't want to rock the boat. You've got a house and a kid and a new home-entertainment center and you don't want to saw that world in half.  Cobb fucked his wife's sister, then left both of them, moved to New York. I want the whole thing, you know? he says. Dorian left his wife, too.  Days after she'd been told by her husband that he's leaving not for anyone in particular but only because he doesn't love her anymore, the Lorax was looking at the family computer. She found an e-mail from her husband to a French Vietnamese woman, the Temptress. It was in French and it said:  I cannot believe I came 00 times in one day. I will never have prostate cancer.  The Lorax's husband came to her from another woman. He left the first Lorax for the second Lorax, and then left the second Lorax for the Temptress, who was two decades younger.  When I see a woman on the subway in her thirties, I hate her, says the Lorax. Every woman in her mid-thirties, I hate them all. I've never felt that way before. But as anyone who has been cheated upon will tell you: Once a cheater, always a cheater. When the Lorax is finally able to get through a full day without crying, it's this thought that buoys her, that he'll do it to the Temptress, too.  Don't you feel bad for the woman alone in the kitchen? says a friend of mine.  Yes, I say. But not as afraid as I am of being her.  I tell a man I meet at a bar about what I'm writing because I'm looking for approval from someone I don't know. He listens and says, Why don't you just argue against monogamy? I'm quiet, I drink my elderflower drink. It's daytime in a great hotel bar on a Saturday and the first few sips of alcohol on an empty stomach always make me feel like I'm happier being on the side that I'm on. His question is smart and important. The answer, the one in my head I'm not sure I want to say out loud, makes me sick, even through the filter of liquor.  I'm more comfortable talking about sex than about love. Or I'm more comfortable saying I want the former than I am admitting I need the latter. Why I don't argue against monogamy is that I'm not evolved enough, maybe, for an open relationship. Most of us aren't. We're marriage animals. But I'm also not trusting enough  -  or naive enough  -  to believe in giving up the illicit. Why I don't argue against monogamy is that part of having great moments, I fear, is having both. The monogamy and the illicit thing, and the passion and the guilt that bridges those two foreign countries, are what deepens our layers, even if some of those layers end up morphing into the slick crusted scales of a snake.  On a Saturday the Enigma calls me.  Oh my God, she says. I did it.  Where?  A hotel. Oh my God.  Tell me about it.  Driving there, I felt like a virgin. I got there and he opened the door and he was wearing these great jeans and no shirt and I was like, Really? We had some wine and at first he just laid on top of me on the bed, like it just felt great to have his body on top of mine. Up till now it's just been him brushing his hand against my ass in the elevator, and I have almost been able to come from that.  What about the taxi? I say.  Oh, right, and the taxi, she says, because affairs are full of half-truths, varying truths. You tell one friend there's a guy you have a crush on, another friend that you kissed him, and another you tell that you take cabs with him because cabs are the only safe place and you straddle him in the cab and he puts his hands on your ass and you make out like animals. And then you forget who you told what.  So how was it?  Words can't describe. I was wearing a thin white button-down and like, our bodies together, holy shit, it was so hot, I mean the first time was like crazy, like we had to get it out. It was fucking crazy. The second time was slower. And the third time we did like everything we missed, crazy positions, oh my God, we did it everywhere.  Oh God. Okay. What are you going to do?  I don't know. Tell me what to do. I love X, but I don't know if I can live a life with him knowing what's out there. But I think I can, I mean, I'll have a normal, good life with X.  You know how I feel.  You don't think I should get married.  Yes.  But don't you think people should have last flings? I mean. You sort of told me I could do this.  Yeah, I meant that. Mostly because I think if you didn't do it now, you'd do it after a few kids, and that's worse. I just think it's too early for you to feel this way.  What if I just do this my whole life?  I think you might.  I feel so bad.  You sound excited.  Fuck you.  Maybe an actual individual needs to heal you, says a friend of mine to me. Maybe your parents' death fucked you up and you need someone who's going to change your mind about everything. My brother says to me, Whatever you do, don't get married.  There is a boy I meet in New York who lives in Los Angeles. I know his father professionally. I don't think he's the one by any stretch. Even if I did, I wouldn't admit it to anybody, especially to myself.  People in affairs are hackneyed. They talk about what would have happened if we had met five years ago, seven years ago, twenty-four years ago, if you had been alive then. Nothing probably, is the answer. A Tom Waits song would have come on in the bar and you would have decided her hair was too red or her laugh was too loud. But you can't have it now so you need it.  Maybe my friends are right, and I'm a little broken. But since the death of my parents, it's been easier for me to associate with the devils. I've never been cheated on, to the best of my knowledge, and I know women who would like me to feel it. I understand that. I'm sorry for them, and mindful it can happen to me. Because you are on one side, until you are on the other.  The boy in L.A., his father is slightly mad and also slightly estranged from his son. The father says, You're writing about affairs, hmm? Why don't you write about my son, who is cheating on his fiancée with you?  At first I'm a little gutted, if you can be just a little gutted. It takes me a couple of hours to regroup.  I take an exercise class in Manhattan in which women with clean soy faces and Lululemon everything and Klonopin-sized engagement rings do pliés and lunges and glute moves and everyone looks like swans in mirrors, one long shiny black leg up in the air and the other finding purchase in a powder-blue rug. I feel like an interloper, even though I'm wearing Lululemons, too. There are two women in here who I know have been cheated upon. I know their fiancé and boyfriend and I know what they did with two girls.  I stare out across a roomful of them, Dove deodorant and girlish sweat lite, a shiny black smooth pool of them, pulsing to Rihanna, BlackBerrys blinking up at them from the floor and the swans diving down to do standing splits, getting a closer look at the screen, which maybe says, Out w Brian. Call you later. And the swans reposition like I do, into wide second positions, their Lululemons stretching out like goalposts, they inhale deeply and pulse to the music, gracefully stretching themselves until they can bend all the way in opposition, waiting to become a plateful of olive pits, and me in the corner stroking my scales, until each of us switches positions again.  