La Notte (1961) a.k.a The Night
A wife has a chance to get back on her cheating husband but does not take it.
Europe
Sex Games for Couples (1976) aka Fantaisies pour Couples – France
Two couples are cheating with each other’s spouses before having an official wife swap.
Young Adam (2003)
A drifter screws the barge captain’s wife. Starring Tilda Swinton, Ewan McGregor, and Emily Mortimer.
All Ladies Do It (1992) – Tinto Brass
A husband gets turned on when his wife tells him of her infidelities because he thinks they are just her fantasies but gets mad when he finds out that she is actually telling the truth.