The actor, who is still struggling to save his marriage following his fling with mistress Emily Goodhead, confessed he came close to suicide while taping an episode of reality show True Tori, which aired in America on Tuesday night (29Apr14).
Opening up to the couple's therapist, MCDermott said, "We're sitting here in the room where I had my breakdown. I've been looking at that crack in the window. I remember looking at that crack and while we were waiting for the Emts (emergency medical technicians), I was thinking, 'I've got a window of opportunity here to kick that out... and just dive out'.
"I didn't do it but I mention it to show how far I'd gone down the rabbit hole - and that the only way out was for me to leave this earth.
"The days leading up to my breakdown, I wanted to disappear. I just thought, 'This is it. You can't get out of this'. I just thought Tori deserves me to die. And I sit here today looking at that (crack in the window) and I know I will not take my life.
"My life means a lot to me now where it didn't for so many years. I'm getting the help I need and I'm surrounded by love and support. That's what's going to keep me alive... I deserve to live."
Following his breakdown, MCDermott checked himself into a Los Angeles rehab facility to deal with "health and personal issues".
Meanwhile, his actress wife is still struggling with MCDermott's infidelity - she was recently released from hospital after secretly spending six days in a Los Angeles medical centre for undisclosed issues.
The former Beverly Hills, 90210 star was spotted heading home on Saturday (26Apr14) afternoon, still sporting a hospital Id bracelet on her wrist as her husband helped her into a waiting vehicle.