John Stamos Says Former GF Teri Copley Cheated with Tony Danza: ‘It Was Awful’

John Stamos is opening up about past heartbreak in his new memoir “If You Would Have Told Me.”

In the book, he recalls how one of his former girlfriends, “We Got It Made” star Teri Copley, cheated on him with fellow actor Tony Danza back in the 1980s. Copley, however, insists she and John were over when she moved on with Tony.

Sharing the story with People, Stamos said finding Teri in bed with Tony was “physically painful” and “worse than anything.”

“I can’t explain it, but I would’ve rather been punched in the nose again or something because the pain is so overwhelming,” the “Full House” actor said. “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.”

Stamos recalls finding Teri and Tony in bed together in Copley’s guest house. He didn’t recognize Danza at the time, but noticed the man had “ripped abs.”

In shock, John was “breathless” and said he stumbled out of the room.

“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**k it.’ And I ran,” he said. “But I remember running down the driveway with tears streaming down my face and I didn’t want anyone to see me.”

Teri remembers it quite differently! She told People, “I wondered, ‘What was John doing there?’ because we had broken up. He just looked at me and shook his head, and walked away.”

In the book, Stamos noted how he figured out the other man was Danza, explaining he saw a poster of Copley on the front seat of a car parked outside. It was signed to “My Dear Tony.”

In an excerpt posted by Entertainment Weekly, Stamos also wrote in the memoir, “I jump in the El Co, start the car, and Elton John is still singing, and that’s when it hits me. I mouth the words to his most famous lyrics and realize the name of my rival: ‘Hold me closer, Tony Danza…’”

John told People, “It took me a long time to get over that,” adding that Copley is “just a nice person.”

“I mean, it wasn’t right to cheat on me, but I was too immature; I wasn’t a man,” he said. “I didn’t become a man for a long time, and I think she was… I don’t know. I was broken.”

Stamos also thinks everything “evened out” in the end.

Tony’s show “Who’s the Boss” was the lead in to “Full House,” and John told People, “Back then you go, ‘Life isn’t fair.’ And then, ‘Oh, wait a minute. It got evened out.’ I honestly believe if we didn’t follow his show in the summer, that would’ve been one and done for that show, ‘Full House.’”

“If You Would Have Told Me” hits bookstores October 24.