Tamra Judge is spilling secrets.
In the new tell-all book Not All Diamonds and Rosé: The Inside Story of the Real Housewives From the People Who Lived It — written by PEOPLE contributor Dave Quinn — Judge, 54, reveals the one major secret she says she kept while filming the early seasons of The Real Housewives of Orange County.
Judge claimed that during season 4, she once discovered then-newcomer Gretchen Rossi "kissing" another man while she was engaged to fiancé Jeff Beitzel, who was 24 years her senior and had been diagnosed with cancer.
"Gretchen and I were good for a while," Judge said in the book. "The problem was, Vicki [Gunvalson], Jeana Keough and I were out at an event at the St. Regis one night, and we saw Gretchen there with this younger guy, sitting on his lap and kissing him."
Judge claimed she approached Rossi and asked where her engagement ring was, but was quickly brushed off. "She said, 'Oh, it's in my purse, it's too big and it keeps falling off,'" Judge recalls.
Rossi, 42, declined to participate in interviews for Not All Diamonds and Rosé and did not immediately return PEOPLE's request for comment.
Later on, Judge said she once again tried to talk to Rossi about the situation, who confided in her about her relationship with Beitzel.
"We had our first heart-to-heart," said Judge. "She told me, 'Listen, I met Jeff, we dated off and on, it wasn't a great relationship. We were broken up and then got back together. Had I known that he was going to get leukemia and I'd have to be his caregiver, I would have left a long time ago.'"
Moved by Rossi's candor, Judge said she decided not to say "a word" about the incident with the other man.
"I thought it was really brave of her to tell me that," she said. "So I never repeated it, never said a word about it while we were filming."
But Judge said tensions began to simmer after the man, who identified himself as Jay Photoglou, contacted her claiming to be Rossi's boyfriend and alleged that they were still involved. According to Judge, Rossi claimed he was an ex-boyfriend and "stalker."
"As the season went on, it got a little disgusting to me to see her playing this role as if she's engaged and in love with this poor man who's dying, knowing full well that she didn't care about him," said Judge.
"I was just so mad because so much stuff happened off camera, and on camera Gretchen didn't want to admit any of it," she continued. "That's why we continued to fight as time went on. I felt like I was loyal to what she had told me about Jeff. I never repeated it, but knowing that I knew that, she treated me as if I was out to get her."
Beitzel died in 2008 following his battle with cancer. Though Rossi adamantly denied it at the time, she was later rumored to be involved with Photoglou.
In 2010, Rossi filed a lawsuit against Photoglou, claiming he lied about her being unfaithful to her late fiancé, according to court papers previously obtained by The Blast. (She denied the cheating allegations.) She also claimed he stole her personal property, including nude photos released online, and threatened her. After a jury awarded Rossi $523,250, Photoglou reportedly filed for bankruptcy in 2012 and "attempted to have the judgment discharged."
In 2018, a bankruptcy judge ruled that Photoglou could not use his bankruptcy filing to avoid paying the damages award, according to the documents.
While Rossi went on to find her happy ending with now-husband Slade Smiley, her relationship with Judge never quite recovered.
"We just never recovered from that first-season fight," Judge recalled in the book. "But the drama between us was good for the show."
Not All Diamonds and Rosé: The Inside Story of the Real Housewives From the People Who Lived It is out now.