PEOPLE has an exclusive clip from the explosive Vanderpump Rules season 6 premiere and the shocking allegation that might split Jax Taylor and Brittany Cartwright up for good

Well, in a clip from the premiere episode exclusive to PEOPLE, that allegation comes to the surface. And boy, is it a doozy.

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According to former SUR employee Faith Stowers, who previously appeared on Vanderpump Rules during its fourth season, Taylor cheated on Brittany Cartwright — with her!

Image zoom Jax Taylor and Brittany Cartwright Charles Sykes/Bravo/NBCU Photo Bank/Getty

“Faith said that Jax and her had sex,” Tom Sandoval tells his castmates while they all gather to celebrate Scheana Marie’s birthday.

The news quickly spreads around the party, with Taylor denying it. “I didn’t do s—,” he tells Kristen Doute.

She’s not convinced. “I want to bash Jax’s balls in with a sledgehammer. Like, over the pants so I don’t have to look at it,” she tells the audience, before taking her anger out on him. “You stupid son of a b—-. You don’t get to come home tonight so stay at [someone else’s house]. Go f— yourself, Jax.”

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Cartwright is beside herself, spilling the news to SUR owner (and Real Housewives of Beverly Hills star) Lisa Vanderpump before confronting Taylor.

“I am disgusted, per usual, by you,” she says. “If I find out this is true, I’m moving the f— out, I’m taking the dogs with me, and you can rot in f—ing hell.”