The French Love (1972)

Bryan is an American journalist, married with two young daughters. Assigned to cover the Paris Conference on Vietnam, he is approached at the airport by two stewardesses, Corinne and Lucile. They meet again, talk politics, but the discussion veers off course: “Do you know how to make love? - Of course, I'm married.” Bryan sleeps with Corinne as Lucile looks on, then confesses to both women: he feels no remorse, but he's sad that it's so easy to cheat on your wife. “Corinne is a free woman,” as Lucile later tells Bryan. The latter is too puritanical and romantic to accept being just another fling. He thinks of nothing but the young woman, and is constantly on the lookout for her.