For years, Tarek El Moussa built a fortune buying the ugliest, nastiest, most rundown houses he could find and transforming them into every homeowners' dream. But his most impressive flip to date might just be his own life. 

Reeling from the one-two-three punch of back-to-back thyroid and testicular cancer treatments and a back injury, "I was a mess for quite a few years," the Flip or Flop alum admitted in an exclusive interview with E! News' Francesca Amiker.

With his hormones out of whack, he was already dealing with anxiety, panic attacks and depression. "And then I was on opiates for about a year: Percocet, Dilaudid, Vicodin," he revealed, detailing how the treatment for his back injury made him drop 75 pounds. "You could see the bones in my chest." 

Still seeking out remedies for his myriad ailments, he began taking testosterone injections, "And that was the end of me," he said. "I did not react well to the testosterone and my hormones were all over the place because I had no thyroid." As a result, he continued, "In 2016 my life imploded."

The pressure continued building until that May day when he hopped over the back fence of his and then-wife Christina Hall's 6,366-square-foot Yorba Linda, Calif. home, a .38-caliber pistol in hand. 

Though his intention was to simply "blow off some steam," as he put it, he can see why Christina assumed the worse, calling police to report her husband was potentially suicidal.

"I knew there was a major problem because inside, I was dying," Tarek recalled. "It's so hard to explain. People that are suffering with mental health issues, you can't control it. It's almost like it's out of your hand. And then you throw in the testosterone and the hormones and the pills and you're just not the same human anymore."

Seven months later, the telegenic HGTV pair announced their marriage was over. 

"Christina left me and it was heartbreaking," said Tarek, admitting he felt a lot of anger about her decision. "At the same time, looking back 20/20 hindsight, you know, I understand why she did."

Struggling with his emotions and scarcely involved with their two kids—daughter Taylor, now 13, and son Brayden, now 8—"I wasn't a great dad," he admitted. "I wasn't even a good dad. I wasn't around. I was stressed all the time."

Bottom line, he summed up: "I know I wasn't a good guy. But at the same time, I know that wasn't me. I was sick. But I had done so much damage that it was at the point of no return."

So he took it all down to the studs. 

"The best thing that happened to me in my life, and the worst thing, was her leaving," he explained of Christina's decision. "Because it forced me to completely rebuild my life."

As he details in his aptly named Flip Your Life: How to Find Opportunity in Distress — in Real Estate, Business and Life (out Feb. 6), "I put in the work," the 42-year-old said. "We're no different than a house. A house could have a plumbing leaks and mold and no electric and the roof caving in. Well, can you remodel the house and make it look brand new? Well, yeah, of course. You can do the same thing with a human. And I'm a big believer in flipping your life from the inside out."

To continue the analogy, his demo day took place a few weeks after Christina left him. 

Living on his 50-foot yacht fittingly dubbed "Bad Decisions", he was drinking a lot and eating very little. "One day I was just hanging out, passed out, hit the deck," he recounted. "When I woke up, my friends were shaking me. They immediately set me up on the phone with Dr. Drew [Pinsky] and I ended up moving to a halfway house."

Without that rock-bottom moment, he continued, "I don't know if I would have made it." 

Fast-forward nearly eight years and one marriage to Selling Sunset standout Heather Rae El Moussa (née Young) later and he's the equivalent of an 8,000-square-foot oceanfront property with a wide-open floor plan and a six-figure view. 

"I'm just so close with my kids," he said of his brood, which now includes 12-month-old Tristan, his son with Heather. "It's crazy to think how close we are, like we are best friends. And then looking back years ago, we didn't even know each other. I think about all those those moms and those dads out there that have all these negative feelings and bad relationships with their kids and I just want to tell them, 'You can fix it, you've just got to invest the time.'"

The real estate developer, who's portfolio now includes a slate of HGTV series like Flipping 101 and The Flipping El Moussas, has also sunk quite a bit of effort into repairing his relationship with Christina. 

"Enough time has passed to where all the anger and rage and the negative thoughts, I feel like they're finally gone," he explained of how they've built up a successful co-parenting relationship that includes Heather plus Christina's husband of nearly two years, Joshua Hall. "I was upset that she left me. She was upset that I acted the way I acted. We still had to work together. It took a big toll on our family." 

Now, he continued, "We're very friendly. I would say we're friends today, actually. We talk, we co-parent. She has an amazing relationship with my wife, Heather. It really comes from forgiveness because you can't co-parent if you're angry."

In other words, they took one of the worst houses on the block and...

"There was a moment shortly after she left me," Tarek recalled of his lowest moments, "and I'm driving up and down Newport Boulevard in Newport Beach. And I'm screaming, I'm crying, I'm yelling, 'This isn't fair. That's not fair.' And then the word 'fair' hit me. And then I realized something. I said, 'Life's not fair.' And the second like, I said it out loud, 'Life's not fair,' was the second I started rebuilding my life. Because it was acceptance that it's not fair. So because life isn't fair, you have to do the best you can with what you got."