This is from the 1950s, I believe, and in B&W. I don't think it's Twilight Zone, as I have gone through their episodes. The story supposedly takes place in the future (1970s!). A middle-aged white man is bored with his wife and gets a doppelganger robot to take his place so that he can go have fun while the robot hangs out with his wife. Eventually, the robot decides he wants to permanently replace the man, and he kills him somehow.
Likely an episode from Alfred Hitchcock Presents named "Design for Loving". It first aired in 1958 and the episode is B&W. It was based on the Ray Bradbury short story "Marionette's Inc".