Zack Elliot is a successful young oncologist in the Los Angeles area married to Claire, an equally successful television network executive during the early 1980s. They first met when they were both in college, have been married for eight years, and are generally happy in their relationship, sharing a love for Gilbert and Sullivan and the poetry of Rupert Brooke, to whom they were introduced by their elderly former neighbor, Winnie Bates. Intending to start a family, the couple buy a big house.
Unknown to Claire, Zack has been struggling with feelings of attraction to other men. He picks up men in his car and starts frequenting gay bars in West Hollywood on his lunch hour, although he does not follow through sexually. This changes when he meets Bart McGuire, a gay novelist who comes to see him for a medical check-up. Bart leads a fairly hedonistic single lifestyle, picking up multiple sexual partners, frequenting gay bars and clubs, occasionally taking recreational drugs. Zack and Bart are mutually but unspokenly attracted to each other and go out for lunch.
A few days later, Zack asks him on a dinner date. He lies to Claire, saying he has to work late. At Bart's house, it becomes clear Zack is not yet able to identify as gay, instead labeling himself "curious." Zack and Bart go to bed, which is the first time Zack has had sex with another man. Zack wants to stay the night, but Bart, following his usual pattern, brushes him off. Angered, Zack leaves, but later challenges Bart's fear of intimacy, which stems from his own troubled childhood with his domineering and emotionally abusive father growing up. Bart makes plans for them to get together during the weekend.
Claire, concerned about the growing distance in her marriage, goes to her boss seeking a year-long leave of absence. Instead, he promotes her and sends her to New York City on a weekend business trip. Zack takes advantage of the opportunity to spend more time with Bart, but they end up arguing. Zack calls the outline for Bart's new novel less than honest, and Bart confronts Zack about his own lack of honesty about his sexuality. That night in bed, Zack tells Bart that he loves him. The next morning, fearful of his own growing feelings for Zack, Bart pushes him away again.
Eventually, Bart realizes that he does have feelings for Zack but that he is not ready for the level of commitment that Zack needs. He is last seen in the film out in the bars, cruising.
When Claire returns home from her trip, Zack tells her of his feelings for other men. Although she said she could handle anything he could tell her, she reacts very badly and Zack leaves the house. A few days later, an emotional Claire trashes some of Zack's clothes and finds a matchbook with a man's name and number written in it. She locates someone Zack had picked up, and they talk. She learns that he lives a relatively normal and happy life. Claire attempts to get Zack to remain in the marriage, even claiming that she would be okay with him having affairs with other men, but Zack advises her that she must let go and that he can no longer continue to live a lie and needs to be true to himself once and for all. Zack then tells Claire that he has a job prospect in New York City, working with cancer patients. In the end, the two agree to a divorce.
The film ends a few years in the future, with the death of Winnie Bates, Zack and Claire's former neighbor. Zack is living in New York and in a committed relationship with another man, an investment banker, named Ken. He returns to Los Angeles for Winnie's funeral. Claire has since gotten remarried to an architect, and has a young son named Rupert. It is loosely implied that she is now a stay at home mom. After the funeral, Zack and Claire discuss their lives and express their own happiness and their gratitude that the other is happy.
Throughout the film, Bart and Claire deliver several mini-monologues, speaking directly to the camera about aspects of their lives and their feelings about the scenes that had just played out on-screen.
