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.