Stassi and Katie Storm Out of Kristen's Apartment After Screaming Match with Carter on 'Vanderpump Rules'

Oh, boy. Monday's "Vanderpump Rules" was messy.

Well, not all of it. Stassi Schroeder met Beau's mom, and the two hit it off. We've seriously never seen her so happy. Oh, and Lala Kent made up with Randall Emmett. She even got her Gucci slides back.

But things were not so peachy for Kristen Doute and Brian Carter, who wound up getting into a screaming match with Stassi and Katie Maloney during a -- get this -- couples therapy session in their apartment.

Beau's mom is a sweet lady who also happens to be some kind of relationship expert. She agreed to come over and give the group relationship advice because, as Stassi pointed out, her friends need all the help they can get.

ICYMI: Kristen had a drunken meltdown a few episodes back while the girls were all in Solvang. Stassi and Katie ended up revealing a lot of stuff about Kristen's relationship she had confided in them individually, but never as a group or in front of cameras. They said Kristen constantly tells them she's miserable, that her and Carter fight all the time, that he doesn't pay for anything and that he's just an overall flop of a dude.

This week, Katie revealed that Kristen and Carter don't have sex, let alone sleep in the same bed. Kristen couldn't refute it, but she was visibly uncomfortable. Naturally, word got back to Carter that the girls were railing on him, so he confronted them about it during Monday's new hour. He found them sitting and chatting in his and Kristen's bedroom, away from the big group that was sitting in the living room.

Taking a seat on the bed, Carter looked at Katie and said, "You and Tom have been together for what -- six, seven years?" Katie replied, "Eight years."

"Y'all have hit a little bit of lulls, a little bit of bad patches, and yet, you're still gonna grow," he said before turning his sights to Stassi. "You and Beau -- I'm so proud of you guys. Like, he's the best man ever, but I don't get why you guys have to bad-mouth me."

Katie maintained she was never talking smack about him, simply "regurgitating everything that [Kristen's] said." Carter insisted she and Stassi only ever hear "the bad stuff."

"Look me in the eye and tell me that you guys are in an awesome relationship!" Stassi shouted. "I have text messages [from Kristen] always saying, 'I need to get a Xanax. I need to get some weed. I need something because Carter's being mean to me.' For years."

Carter's tone changed instantly. "I'm getting relationship advice from someone who hasn't been in a good relationship until three months ago?" he fired back. Stassi didn't disagree.

"We have been dating for almost three years now, and there was a little rocky patch. I will admit that. I did not handle my shit right," Carter said. Before he could finish his thought, Stassi said she felt "uncomfortable" having such an intense conversation about her friend's relationship while sitting on her bed.

"You know what's awkward? Is sitting there and having to listen to Kristen be so upset, be miserable for so long, for the way you treat her!" Katie shouted.

That's when Carter shifted the blame to Stassi and Katie, telling them they're the reason he and Kristen don't get along. "You guys are f--king dicks to her," he said. "You guys are f--king rude. I'm sorry!"

Stassi and Katie were fuming. "She comes home and gets in fights with you because of me and Katie?!" Stassi asked Carter, looking for clarification.

"Because you guys are scary," he answered smugly. "Y'all scary."

When Kristen walked in to try to mediate, Stassi began loudly explaining to her what had just gone down.

"So No. 1, stop yelling in my house," she said calmly as she took a seat next to Carter.

"You guys do enough yelling here. I know. I get it," Katie fired back.

No matter what Stassi and Katie tried to say, Kristen interrupted to tell them to lower their voices. Eventually, they snapped.

"Everything I said about him to you were things that you had said to me!" Katie said as she got into Kristen's face. Stassi added, "We are not making anything up, Kristen!"

Shocked, confused and "insulted," Katie left the apartment, as Kristen announced to her guests she was going to "sage this motherf--ker." Turns out the "motherf--ker" was Stassi.

"Kristen saged me!" Stassi shouted during a later confessional. "She saged me! Kristen has spent the first 35 years of her life in a blind, vengeful, drunken rage -- helicopter punching anyone who's in her path. Then she meets Beau's mom, and all of a sudden, she's Mohandas Gandhi and saging everyone in her apartment? Give me a f--king break."

Soon after, Stassi bid her goodbyes and left, too.

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

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