A Black Veil for Lisa

When a narcotics detective finds out that his beautiful wife (who is an ex-criminal) is cheating on him, he hires a professional hitman to bump her off. However, things don't go quite according to plan. The detective was involved in investigating a string of drug-related murders, and when he finally catches the killer Max Lindt, instead of arresting him, he surprises him by asking him to murder his unfaithful wife. Instead of killing the woman, the hitman ends up sleeping with her, and they begin an affair.