John Stamos Claims He Caught Girlfriend Cheating With Fellow Sitcom Star

John Stamos claims he caught former girlfriend Teri Copley in bed with Tony Danza back in the 1980s. The Full House actor, 60, writes about the incident in his new memoir If You Would Have Told Me, telling PEOPLE that seeing the model in the arms of the Who's the Boss? star 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," he told the outlet. "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 in his book walking into Copley's guesthouse to find her sleeping in bed with a man with "ripped abs" he didn't immediately clock as Danza. Running down the driveway in tears, Stamos said he only identified Danza after seeing a poster of Copley she'd signed "My Dear Tony" in a car he didn't recognize parked at her home. "I jump in the El Co, start the car, and Elton John is still singing, and that's when it hits me," Stamos writes in his memoir, as per Entertainment Weekly. "I mouth the words to his most famous lyrics and realize the name of my rival: 'Hold me closer, Tony Danza. . . .'"

Copley, 62, told PEOPLE that she and Stamos were already split up at the time, recalling, "I wondered, 'What was John doing there?' because we had broken up. He just looked at me and shook his head, and walked away." The Big Shot star also described Copley as "just a nice person" to the magazine, calling himself "immature" at the time of their ill-fated relationship.

Stamos also thinks things evened out with Danza in the end, as he credits Who's the Boss? with Full House's early success, as the popular sitcom led into what would eventually become Stamos' biggest success. "Back then you go, 'Life isn't fair.' And then, 'Oh, wait a minute. It got evened out,'" the actor told PEOPLE. "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 is available now wherever you buy books.