McDermott posted, then deleted, a message announcing his split from Spelling in June.
"My worst memory with Tori is that last fight when I was drunk and angry," he told the Daily Mail in the second part of his revealing interview. "It was the night that I raged against her and the children and I saw the light, the final flicker of the flame go out in her eyes."
He added, "I posted that because I was at the end of my rope. I didn't know what to do. I had burned everything down yet again."
Following the fight, McDermott -- whom admitted that he was drunk and high at the time -- took to Instagram and shared a message announcing the end of his and Spelling's years-long marriage.
"It’s with great sadness and a very very heavy heart that after 18 years together and 5 amazing children, that @torispelling and I have decided to go our separate ways, and start a new journey of our own," McDermott shared in a since-deleted Instagram post from June.
"We will continue to work together as loving parents and guide and love our children through this difficult time. We ask that you all respect our privacy as we take this time to surround our family with love and work our way through this," he wrote.
According to McDermott, after he shared the post, he took several Ambien sleeping pills with the hope that he would not wake up the next morning.
"After I sent the post, I took some more pills, and I took six or seven Ambien in the hopes that I would not wake up," he shared with the Daily Mail. "Thank God I did. Thank God I did. Because I would've ruined so many lives if I had died."
Together, Spelling, 50, and McDermott, 57, share Liam, 16, Stella, 15, Hattie, 12, Finn, 11, and Beau, 6. McDermott is also the father of Jack, 24, from a previous relationship.
McDermott shared that he is currently living in a sober living home, after completing a 40-day rehab stay. Though he is no longer with the Beverly Hills 90210 star, McDermott -- who is in a relationship with Lily Calo -- says he was hurt when he saw pictures of Spelling kissing ad exec Ryan Cramer.
"I did see the photographs of Tori kissing another man, and it hurt, I'm not going to lie, but she saw the same thing with Lily," he told the site. "She's given it to me for 18 years and I've been so hard and brutal on her that I just want her to be loved and happy. She deserves it."
Early this month, a source told ET that Spelling is embracing her new chapter and the early stages of her new relationship.
"Tori is having fun and enjoying getting back out there," the source said. "She doesn't mind that the news of her dating is public. She is moving on too from her relationship with Dean. Things are still new with Ryan and they are talking and getting to know each other. He's a chill guy and that's nice for Tori right now. Her friends are surprised by the recent romance, but also happy for her."