Stanley Tucci in Sex and the Other Man
(1995)

In this adapted play, Billy (Ron Eldard) finds his wife cheating on him with her boss, Arthur. He ties up Arthur and forces him to watch them make love. As it turns out, this cures the performance problem Billy's been having, so he decides to keep Arthur around. Unfortunately, Tucci and Eldard aren't able to rise above the weak script here, so if you find this movie somewhere, I suggest fast-forwarding through it.