Unfaithfully Yours (1984)

Claude Eastman, a composer and conductor, is married to Daniella, who is half his age. While away on a trip he tells his Italian driver Giuseppe, to tell his friend Norman to keep an eye on her, or take care of her. But his English is not too good, so Norman thought he was saying that Claude wanted him to hire a private eye to keep tabs on her--which he did. Claude tells him that it's OK, but the man Norman hired gives him his report: something happened while he was away. Claude, of course, tells him to throw it away, but after Norman leaves, Claude tries to retrieve and read it, but Daniella's there. When Giuseppe destroys it, he goes to the man Norman hired to get a copy. He tells Claude that a man went into his apartment while he was away and left at an unusual hour, and that he also has a video. Claude tells him to destroy it,, but shortly after leaving returns so that he can watch it. The video's a little fuzzy but he clearly sees a particular item of clothing the man wears, so he checks every man he knows to see if they wear that item. He discovers that ladies' man Max, his protege', wears it. He confronts Daniella, who tells him it's nothing, although she is harboring some kind of secret. Claude freaks out and plans to kill Daniella and frame Max for it, but an unforeseen circumstance disrupts his perfect plan.