Your assumptions about my relationship are pretty deeply unfounded--I've never been forced to visit her family, nor do I hate her friends, nor have I ever been forced to visit them. There's no "whipping" involved--I'm every bit as free as I care to be.

It's not a question of power at all--we don't seek power over each other so much as we work hard to keep our autonomy while sharing our lives together. It's difficult, but it's worthwhile as well. Building a strong relationship that respects the freedom of each partner is just as hard as keeping up one side of a power game, but it's more fulfilling in the end. Knowing that someone else truly and deeply loves you is a very comforting feeling, especially when you both know it's mutual. Trying to withhold that satisfaction and make your partner insecure just to keep her (literally) on the treadmill is an asshole thing to do, but ultimately it hurts you too. Winning your power-game style of relationship would be hell to me compared to the relationship I actually have.

Look, I'll just address you point-by-point:

Moreover, if she's constantly terrified that you'll leave her if she gets fat, she'll exercize often and stay in shape, so that she can sexually arouse you for years to come, thus disincentivizing you from dumping her when she hits the magic 30-year-old mark.

Fat girls are underrated in my opinion, but there are plenty of strong women who can and do keep themselves in good shape for their own benefit. Of course, a self-starting woman like that is likely far too strong to put up with the kind of bullshit you're talking about.

You reciprocate by paying attention to her, by pretending to listen to her illogical / irrational arguments

I would rather not date stupid and irrational women. I prefer women whom I actually like paying attention to. Especially for a lifetime commitment!

and by abstaining from (too much) philandering

That's not a special favor; that's a basic part of being in a monogamous relationship. If monogamy is boring, have an open relationship and let the girl have some fun too. It might even spice up your sex life to have the odd threesome!

The kind of relationship you advocate might be the best you can get--it may be genuinely difficult to have a genuinely good relationship like I'm talking about--but personally speaking, if the best relationship I can get is some adversarial power game, I'd rather go completely without. I have no fear of dying alone--I am comfortable with the notion.

My personal suspicion: old married couples who treat their relationship like a power game are not happily married couples--they're like the couple in this story: http://www.violentacres.com/archives/497/happily-ever-after/

Watching them was like watching a sick, evil little puppet show. He goaded her, she attacked him. He ignored her attacks, she escalated. Within minutes, dinner was ruined. They both looked supremely satisfied with this result.

Before I turned to leave, the man reached out with a bony, desperate hand and clutched my arm.

“Never, never get married,” he implored.

I looked at his wife. Instead of looking offended, her eyes widened in tentative agreement. A slight nod of her head was like the period on the end of his sentence.

That couple was trying to save my life."