Belle De Jour (1967)

Severine is a beautiful young woman married to a doctor. She loves her husband dearly, but cannot bring herself to be physically intimate with him. She indulges instead in vivid, kinky, erotic fantasies to entertain her sexual desires. Eventually she becomes a prostitute, working in a brothel in the afternoons while remaining chaste in her marriage.

Director: Luis Buñuel
Stars: Catherine Deneuve, Jean Sorel and Michel Piccoli

IMDB