Phil Potter (Burt Reynolds) splits with his wife, Jessica (Candice Bergen). She wants to be a singer/songwriter and has been having an affair.
Phil moves from New York to Boston, where his brother Mickey (Charles Durning) and his sister-in-law Marva (Frances Sternhagen) live. Against his wishes, they set up him with a blind date, Marilyn Holmberg (Jill Clayburgh), a nursery-school teacher working on her master's degree.
He begins a new life. Phil takes a part-time teaching job and attends a divorced-men workshop in a church basement, meeting lonely men like Paul and Larry whose situations are similar to his. Marilyn feels it's too soon following his breakup for Phil to begin a new relationship. He goes on a date with her friend Marie, a single mom who literally throws herself at him.
At a family Thanksgiving dinner, a phone call from Jessica comes at an inopportune time. Marilyn overhears him telling Jessie that he is dining with his family and "their friend." Marilyn's feelings are hurt and wants to end the relationship. He confronts Marilyn at a School Carnival, where she is staffing a "Dunk the Teacher" dunk tank, and after dunking her several times, Phil asks her to "define" their relationship. Finally, Marilyn agrees when Phil invites her to move in with him. Soon after they move in together, Jessica unexpectedly turns up at his apartment. She looks fabulous and has become a great success as a songwriter, although she is a decidedly off-key singer.
Phil moves back to New York to be with Jessica again. But the more he is with her, the more he misses Marilyn. He returns to Boston only to find she is now dating a basketball player. Phil does everything he can, even disrupting a Boston Celtics practice, in an attempt to win her back.