Una Storia Ambigua 1986 one on netflix

Countess Anna Guerrieri, a rich and provocative noblewoman, marries Romano, an important fascist who is very loyal to the party. Sadly his sexual performance is found very lacking by the Countess, and so frustrated, she decides to look elsewhere for satisfaction and ends up setting her sights on Stefano, a naive and inexperienced young nephew undergraduate who has recently arrived from the provinces.