A wealthy woman from Manhattan's Upper East Side struggles to deal with her new identity and her sexuality after her husband of 16 years leaves her for a younger woman.

Erica (Jill Clayburgh), is unmarried only temporarily in that her successful, wealthy husband of seventeen years has just left her for a girl he met while buying a shirt in Bloomingdale's. The film shows Erica coming to terms with the break-up while revising her opinions of herself, redefining that self in its own right rather than as an extension of somebody else's personality, and finally going out with another man. Erica refuses to drop everything for Saul (Alan Bates), an abstract expressionist painter, simply out of love for him because he expects her to. It is not so much loneliness that is her problem, and the problems that men, flitting around this newly "available" woman like moths round a flame, bring to her sense of independence.