The Alfred Hitchcock Hour S01E31 - Run for Doom

Dr. Don Reed falls in love with a nightclub singer named Niki Carroll despite the warnings of his seriously ill father and her ex-boyfriend who both tell him she is not good for him. Niki accepts his marriage proposal, but Don's father dies when he hears the news. The newlyweds take an exotic honeymoon cruise with the inheritance money. During the cruise, Don becomes enraged when he sees Niki kissing another man and he accidently pushes him overboard. Niki convinces Don to keep his mouth shut and since no one saw the incident he gets away with murder. Niki eventually grows tired of him. She tells him that she is going to leave him. She also wants all his money or else she will tell the police about the murder. Niki also dumps her band leader boyfriend, but instead of accepting this he strangles her. The police call Don to the scene. He examines his wife's body in the bedroom and discovers that she is still alive. Believing that the band leader is going to take the rap for murder, Don finishes her off. When he rejoins the police he is shocked to learn that the police knew that Niki was still alive. They had told the bandleader she was dead in order to calm him down. The police then inform Don that they like to finish questioning her.