Loving Couples (1980)

Synopsis
Susan Sarandon gives a sprightly performance in this sex farce involving couples swapping mates. Shirley MacLaine is Evelyn, a doctor, who is spending some quality time horseback riding when she is spotted by Greg (Stephen Collins), who is driving his sports car. Greg looks at her a bit too long and crashes the car, and since Evelyn is a doctor, she feels free to ride up to the prone Greg and rip off his pants. Soon the two are having an affair behind the backs of Greg's TV weather-girl lover Stephanie (Susan Sarandon) and Evelyn's workaholic husband, Walter (James Coburn). When Walter finds out about the affair from Stephanie, the two decide to reciprocate and engage in an affair of their own. ~ Paul Brenner, All Movie Guide