The Cloning of Clifford Swimmer (1974)

Clifford Swimmer, an angry and abusive man cruel to his wife and son, wants out if his marriage. With the help of a scientist he clones a replacement who takes over as head of the family while the real Clifford travels the world. The clone turns out to be a gentle and sensitive husband and father, a complete opposite of the original, and the wife and son come to love him. When the real Clifford comes back and finds his family happy with the clone he becomes angry and jealous and things take a deadly turn.