Vanderpump Rules: Ariana Madix Is Livid as Tom Sandoval Outs Her for Having Sex with Lala Kent

Vanderpump Rules star Ariana Madix had hoped to keep her private life, well, private — until her boyfriend exposed her hook-up with a female friend.

On Monday night’s episode, Tom Sandoval celebrated his 36th birthday at a cigar bar with James Kennedy, Tom Schwartz, Jax Taylor and Peter Madrigal. When the boys traded ribs about their significant others’ “dips in the lady pond,” Sandoval decided to out Ariana’s sexual encounter with hostess Lala Kent.

“I don’t know if I ever told you this. Ariana and Lala had been out all day drinking, and they’re wasted. They’re in my car, and Lala goes, ‘Sorry, Sando, I’m just in love with your girl right now. Ariana, will you come in the back seat? I just want to eat your p—-,'” he said. “Ariana climbs in the back and Lala just starts going to f—ing town, dude.”

“Did you have a threesome?” Peter asked.

“Couldn’t do it,” Sandoval replied.

Later, Jax runs the story past Lala when she visits him and fiancée Brittany Cartwright at their apartment. Of course, Jax is no stranger to this kind of drama: In 2016, he spread a rumor that he’d caught Kristen Doute performing the same sex act on Brittany. (Both women denied they’d gone any further than drunkenly kissing.)

Lala played it cool.

“No, I did not have sex with Ariana in the back,” she said with a dismissive laugh. “What the f— is he talking about?”

Those acting classes are paying off: To the camera, she admitted it was all true, but she’d lied to protect her friend.

“Did this happen with Ariana and myself? Yes. Am I about to blow Ariana’s spot up with Jax and Brittany right now? Hell no,” she explained.

She went straight to Ariana, who shot Sandoval a withering glare from behind the SUR bar.

“What’s wrong?” he asked.

“Are you f—ing kidding me? I literally just got a phone call from Lala telling me the f—ing story you told on your birthday to try to sound cool in front of a bunch of guys,” she spit.

“It’s not that big of a deal,” he said.

“It’s not a big deal? I’m sorry, but it’s my business,” she replied.

Ariana elaborated in a confessional interview: “I’m not embarrassed or ashamed of what happened between Lala and I, but I do feel like Tom betrayed my trust by telling this story to his guy friends. My sexuality is not something that is meant to sound cool to a bunch of dudes.”

But Sandoval didn’t understand her ire, pointing out, “You’ve been in a relationship with a girl before!”

“Yes, okay. Tom, you told something that is not your business to tell without running it by the people who were really involved,” she insisted.

RELATED VIDEO: Lala Kent Reveals She Is 50 Days Sober

After cooling off, they patched things up at home.

“When you talk about anyone’s sexuality without their consent, it’s like really not okay,” she explained.

His reasoning for gossiping about the hook-up? “There was a part of me that was like annoyed by that situation because you guys were wasted.”

“This is my sexuality as a person,” he said. “I don’t talk about that stuff openly with the entire f—ing world. But now, it’s like, welp, everybody knows.”

Although she doesn’t want to identify as bisexual, “I’ve been with women in the past, and obviously I’ve been with men,” she told the camera. “I would rather not label things and just kind of, if you’re attracted to somebody, you’re attracted to them, and if you’re not, you’re not. And that person can be male, female or anywhere in between.”

RELATED: Vanderpump Rules’ Lala Kent Says Her Car Was Burglarized: ‘Don’t Trust Anybody!’

And Sandoval seemed genuinely sorry.

“I don’t like being that guy,” he said. “You know, you’re like my treasure, and all those things that I know about you, all those little quirks and whatever, they’re like very valuable to me. And let’s just hopefully try to move on from this.”

“I don’t think Tom was being malicious in any way. So part of me is really grossed out and mad at him, and the other part of me is like, you poor little thing. You thought you were being cute,” she said in an interview as they kissed and made up.

Vanderpump Rules airs Mondays at 9 p.m. ET on Bravo.