The Unfaithful Wife (1969) Label

Insurance executive Charles suspects his wife Hélène of playing the field, so he has a private detective locate his wife's lover, author Victor Pegala. Confronting Victor, Charles tries to adopt an air of indifference, but the conversation ends with the husband bludgeoning the author to death and then calmly disposing of the evidence. When Hélène is questioned about Victor's murder, she discovers on her own that her husband is guilty. Instead of turning him in, Hélène is so thrilled that Charles cares so deeply about her that she is more in love with him than ever before.