Forbidden Fruit (1952)

Charles Pellegrin, 40-year-old country doctor, buys a practice in Arles, a provincial town near Marseille. In five years, he has a large practice and a lovely (but more efficient than passionate) wife, when he meets spectacularly sexy, sensuous Martine, who seduces him. Soon, he's honoring that old French custom of keeping a mistress. At first Martine brings romance, then passion into his life...then black jealously and despair.