In the inaugural episode of his new Daddy Issues podcast with comedians Adam Hunter and Nicky Paris, the 52-year-old actor holds nothing back as he discusses his reasoning for having an affair.
"I really, really wish that I had been given the knowledge of thinking with your head, not your penis," he admits. "Because I did a lot of thinking with my penis."
The conversation continues over a Cosmopolitan article titled "I'm Cheating on My Husband Because He Refuses to Go Down on Me." McDermott took the opportunity to react to the article based on his own experience with cheating.
"I've been there. I've cheated and it's so not about the person you're with," explains McDermott, who shares five kids, Finn, Stella, Liam, Hattie and Beau, with Spelling, along with another son, Jack, from a previous relationship. "In this particular case, it happened to be or that's her excuse, I think there might be more wrong with the marriage than him not going down on her. For me, it wasn't about T, it was about inadequacies with myself. I felt so bad about myself, I felt like a piece of s**t, I needed to do that to feel some kind of power."
McDermott continues on, telling Hunter and Paris that he remembers the story about his affair breaking on Christmas Eve in 2013. Multiple outlets reported at the time that McDermott cheated on Spelling with actress Emily Goodhand, while they were both filming Chopped Canada.
"A friend sold the story. It came out through the publicist to both of us at the same time," he recalls. "It was horrible and I'm an a**hole piece of s**t for doing it."
"That was a rough Christmas, but we came out through the other end," he adds, claiming their relationship is now "better than ever."
Last August, a source told ET that McDermott and Spelling started counseling again in order to help repatch their marriage following a series of chaotic events that occurred earlier that year.
"Tori and Dean are very much in love and have dedicated themselves to improving their marriage. They built a family together and plan on raising their kids as a team," the source said. "They realized things got completely out of hand when their blowout fights became very public. As painful as that period has been in their life, it was also very eye-opening for them."
"They started counseling again and turned everything around," the source added. "They realized that most of their [recent] stress stemmed from their money issues. They're now working closely with an accountant to help fix their financial situation. They've since made some big changes."
Hear more on Spelling and McDermott's highly publicized ups and downs in the video below