A Lustful Mind (1986)

Original title: Lussuria

Alessio, a young man from a well to do family, has been mute since the death of his mother two years ago. His father, who has subsequently remarried, sends him to his sister-in-law's house in the country to recuperate. While staying there Alessio has erotic fantasies concerning his stepmother, his aunt and a young art restorer working on the estate, all of whom his father is sexually involved with.