The 46-year-old actor, who gained fame playing Clark Kent on the TV series "Lois & Clark: The New Adventures of Superman," got engaged to McCready in 1997. They split the following year.
"I can't paint too pretty a picture," Cain told People on Monday. "She would start arguments, start drama. Things weren't allowed to be good." The actor says "red flags were everywhere" and he eventually moved into a hotel to escape her. "She was kind of poisonous and not somebody I was going to have in my life anymore – or anywhere around my son."
Cain, who fathered a son with former Playboy Playmate Samantha Torres, is single today. McCready went on to have relationships with hockey player Drake Berehowsky, singer Billy McKnight and, most recently, record producer David Wilson. She also had an ongoing affair with baseball great Roger Clemens.
According to E! News, McCready's first attempt was in July 2005 when she overdosed on pills and alcohol. Two months later, she overdosed again on antidepressants while pregnant with her first son. "He turned out to be OK, but there was a third attempt in 2008," Los Angeles Times music writer Mikael Wood told E! News.
In 2008, paramedics were called to her home and she was found with wounds on her wrists. Two years later she overdosed again, but authorities never confirmed if it was accidental or not.
McCready committed suicide on Feb. 17 just weeks after Wilson died of an apparent self-inflicted gunshot wound. Authorities are treating Wilson's death as a suicide but have not yet released the official cause of death, according to Rolling Stone.
Prior to McCready's death, E! News reported that Wilson was trying to end their relationship. "He wanted a way out and he didn't know what or how to get out," a source told E!