During a surprise 42nd birthday party for George Webber, a well-known composer of popular music, he finds himself coping badly with incipient middle age. When he catches a glimpse of a mysterious woman en route to her wedding, he is instantly obsessed by her beauty, and - despite the presence of his lover Samantha Taylor - follows the woman to the church where he crashes into a police cruiser and is stung by a bee. George visits the priest, and learns that the woman is Jenny Miles, daughter of a prominent Beverly Hills dentist. Later that night, Sam and George have an argument about George's failure to give her the attention she needs, his use of the term "broad", and the fact that he and his neighbor (a wealthy porn producer) watch each other perform carnal acts using telescopes. The final straw for Sam occurs when George makes a remark subtly impugning her femininity at which point Sam leaves in a huff.The following day, George and Sam suffer a series of mishaps that prevent them from reconciling, including George spying on his neighbor until hitting himself with his telescope and falling down an embankment, causing him to miss Sam's phone call. In addition, George schedules a dental appointment with Jenny's father, and while in the dentist's chair, subtly leads the dentist into disclosing that his daughter and her husband went to Mexico for their honeymoon. The examination also reveals a mouthful of cavities, requiring the dentist to spend the entire afternoon inserting fillings in George's teeth. The after effects of the novocaine, which are aggravated by his heavy drinking immediately after, leave him completely incoherent and when Sam finally reaches him on the phone she mistakes him for a madman and calls the police. The police storm his house, but recognizing him they leave amicably. He visits his neighbor's house to take part in an orgy just as Sam arrives at his house, and she spots him through his telescope, widening the rift between them.Later, George impulsively follows the newlyweds to their exclusive hotel in Manzanillo, Colima, Mexico. In the bar, George encounters an old acquaintance, Mary Lewis, who suffers from a lack of self-confidence because she blames herself for a series of failed relationships. When they attempt a fling that night, she interprets George's inadequacy in bed as confirmation of her insecurities despite her better-than-average looks and easygoing disposition.One hot day at the beach, George sees Jenny - suntanned and dressed in a one-piece swimsuit and her hair braided in cornrows - which furthers George's obsession. He notices that David, Jenny's husband, has fallen asleep on his surfboard. Pretending to inquire about renting a surfboard, George learns that beyond a certain point are powerful currents that can sweep a swimmer or surfer dangerously far from land. George rents a catamaran, clumsily but successfully rescues David, and becomes a hero. Both Sam and his songwriting partner see him on TV Network News and Sam tries to call him, but George (unaware that it is Sam) refuses the call. David, badly sunburned, stays in the hospital, allowing Jenny and George to spend time alone together, culminating in Jenny seducing him to the sounds of Ravel's Boléro.Although George is initially elated to find all of his fantasies being fulfilled, he is horrified when Jenny takes a call from her husband while in bed with him and casually informs him of George's presence. He is even more confused when David responds with a complete lack of concern (he had called to thank George for saving his life). When Jenny explains their open relationship and mutual honesty, George is appalled; with the thrill of enjoying forbidden pleasures extinguished, he loses interest in Jenny (Jenny, for the opposite reasons, loses interest in him as well) and he heads back to Beverly Hills.At the end of the film, he reconciles with Sam by demonstrating a new maturity and, taking an idea from Jenny, he starts Ravel's Boléro on the phonograph and they make love with the music playing in the background. This is in full view of the neighbor's telescope shortly after the neighbor has walked away in disgust, complaining that he has had enough of providing erotic entertainment to George and getting nothing in return.
Output: Question: Why did Jenny and David marry each other?, Answer: Mutual honesty in an open relationship