A Change of Seasons (1980)

Synopsis
Middle-aged angst is the catalyst for this drama about an older married couple who join up with younger partners. When Karen Evans (Shirley MacLaine) discovers that her husband Adam (Anthony Hopkins) has been dallying around with young co-ed Lindsey Rutledge (Bo Derek), she is furious. She fights back by starting up an affair with young Pete Lachapelle (Michael Brandon) and pretending to tolerate her husband's pecadillos. Adam is selfish and arrogant, a typical college professor stereotype. The odd couples decide to take off for a skiing holiday in Vermont during which their relationships will be tested. ~ Eleanor Mannikka, All Movie Guide