Una ragazza piuttosto complicata / A Rather Complicated Girl (1969)

This erotic sexploitation feature concerns a couple and their pursuit of sexual fulfillment with each other – and their mutually agreed upon third bed guests. Lesbian love angles includes the woman's step-daughter. Alberto (Jean Sorel) is soon left alone when the women decides his services are no longer required. After acting on his erotic fantasies, he is left alone and driven to madness when his girlfriend marries another after leaving with her lesbian lover.

Imdb