Thornton has been married five times. Each marriage ended in divorce. He has four children by three women. From 1978 to 1980, he was married to Melissa Lee Gatlin. They have a daughter, Amanda. Thornton married actress Toni Lawrence in 1986. They divorced in 1988. From 1990 to 1992, he was married to actress Cynda Williams. In 1993, Thornton married "Playboy" model Pietra Dawn Cherniak. They have two sons, Harry James and William. The marriage ended in 1997. Cherniak said Thornton abused her.