'It Was Awful': John Stamos Recalls Catching Ex Teri Copley in Bed With Tony Danza

John Stamos continues to spill the piping hot tea about his past relationships.

Ahead of the release of his shocking memoir, If You Would Have Told Me, the Full House actor, 60, opened up about finding his former girlfriend Teri Copley in bed with fellow television star Tony Danza when they dated in the 1980s.

"I can't explain it, but I would've rather been punched in the nose again or something because the pain is so overwhelming," Stamos recalled of allegedly being cheated on, adding that it was "physically painful" and "worse than anything" he had experienced before.

"Looking back, it's like, probably, she wasn't the right girl for me. So seeing him, realizing it was him and stuff, it was hard. I mean, it was awful," he lamented.

In the tell-all — which will be released on Tuesday, October 24 — the former Glee actor remembered walking into the model's guesthouse to find Copley, 62, in bed draped over a hunky man while fast asleep. "At first, I was like, 'I'm going to kick his…' I didn't know it was [Danza] yet. I see his abs. I'm like, 'Maybe not. F--- it.' And I ran," Stamos recalled.

"But I remember running down the driveway with tears streaming down my face and I didn't want anyone to see me," he emotionally explained.

Despite the sitcom star's heartbreaking account, the We Got It Made alum claimed in a new interview that their relationship was long over when Stamos burst into her home. "I wondered, 'What was John doing there?' because we had broken up," she said in response. "He just looked at me and shook his head, and walked away."

According to Stamos, he only realized it was the Taxi actor, 72, after discovering a poster of Copley she had signed "My Dear Tony" in a car parked outside her home. "I jump in the El Co, start the car, and Elton John is still singing, and that's when it hits me," the Big Shot star wrote in the juicy read.

"I mouth the words to his most famous lyrics and realize the name of my rival: 'Hold me closer, Tony Danza ... '" he penned about the moment. "It took me a long time to get over that."

"I mean, it wasn't right to cheat on me, but I was too immature; I wasn't a man," Stamos added. "I didn't become a man for a long time and I think she was... I don't know. I was broken."

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Despite it being hard to relive the painful moment, the singer felt it was important to write about it in his book. "I really wanted to find relatable things that happened in my life," he explained.

"Because I think everybody thinks, like, 'Oh, this guy's got no problems. I'm sure he's never been cheated on,'" he continued. "It's like, 'Oh, she left me because I don't have enough money,' or 'I'm not good-looking,' or this and that. And then you look at me and I go, 'Well, he had all those things,' People are s-----. And it's life."

People spoke to Stamos and Copley about the alleged cheating incident.

Entertainment Weekly obtained the passage from Stamos' book.