The Alfred Hitchcock Hour: Day of Reckoning

An unfaithful wife taunts her husband that she’s ditching him for a real man. As the drunken couple argue on the stern of a yacht, the normally-timid husband shoves her overboard to drown. The society party-goers on the boat support his tale that the wife accidentally fell over the side that night, & the police believe the husband too. At first, he’s relieved, then gradually guilt takes him over, but friends feel his panicky behavior is grief. The widower blurts the murder to his friends, but his story was so convincing they downplay his confession, not wanting to be involved in an embarrassing murder inquiry. As his internal pressure mounts, the killer desperately seeks a way out.