An Innocent Affair (movie, 1948)

Vincent Doane is in the precarious position of trying to close an advertising account with his rich ex-fiancée. Unfortunately she is more interested in him than in business. Vincent's wife Paula gets suspicious and finally decides to do some flirting of her own to make him jealous. Unknown to her, she chooses cigarette tychoon Claude Kimball. In fact, Kimball hits it off well with both of the Doanes. The question is whether or not their marriage can survive all the shenanigans.