Kaitlynn Carter was spotted kissing Miley Cyrus a few weeks after she announced her split from Brody Jenner
In his latest weekly recap of The Hills: New Beginnings for Cosmopolitan, Pratt, 36, took aim at Carter for getting upset about rumors that she and her then-husband Brody Jenner were in an open relationship on Monday’s episode of the MTV reality show.
“It’s tough for me to listen to Kaitlynn complain about people talking about her allegedly open relationship with Brody when we know she had a thing going with Miley,” Pratt wrote. “She already had something going on with her when these scenes were filming — maybe not physically, but definitely emotionally.”
“No one’s judging you for whatever it is you and Brody do when he’s not sleeping in his car,” he continued, referencing an earlier episode when Jenner, 36, slept in his car after the couple got into a fight. “We just don’t want people to lie about their lives.”
“Maybe you shouldn’t have gone on television,” he added. “It’s called a reality show, hon. And the reality is that Brody’s been talking about your sex life on his podcast for years.”
Reps for Cyrus and Carter have not commented, but Cyrus, who announced her split from husband Liam Hemsworth around the same time photos surfaced of her and Carter kissing in Italy last month, has denied being unfaithful during their marriage.
“I can accept that the life I’ve chosen means I must live completely open and transparent with my fans who I love, and the public, 100% of the time,” she tweeted on Aug. 22. “What I cannot accept is being told I’m lying to cover up a crime I haven’t committed. I have nothing to hide.”
Though Cyrus, 26, acknowledged her history of infidelity in past relationships, she insisted that she did not cheat on Hemsworth, 29.
“The truth is, once Liam & I reconciled, I meant it, & I was committed. There are NO secrets to uncover here,” she wrote. “I can admit to a lot of things but I refuse to admit that my marriage ended because of cheating. Liam and I have been together for a decade. I’ve said it before & it remains true, I love Liam and always will.”
On Monday’s episode, Carter, 31, said her costars lacked “common decency” when it came to keeping details of her and Jenner’s relationship to themselves. Pratt fired back in his recap, “I would love to know Liam Hemsworth’s thoughts on Kaitlynn’s recent displays of ‘common decency.’ “
“You know what I call ‘common decency’? Getting it on at your Italian villa and not in front of the paparazzi,” he wrote.
“Brody Jenner and Kaitlynn Carter have decided to amicably separate,” their reps said in a statement at the time. “They love and respect one another, and know that this is the best decision for their relationship moving forward.”
A source later told PEOPLE the two, who were not legally married, had been having “issues for years” and that The Hills reboot was “not good for them.”
“Doing The Hills magnified a lot of things in their marriage,” the source said. “And it became clear that it wasn’t going to work. They both knew it.”
Despite Pratt’s allegations, Jenner has only spoken highly of his ex.
“There is far too much negativity being directed at someone who I love and care about very much,” he recently wrote in a since-deleted Instagram post. “I feel the need to set the story straight. Kaitlynn and I have been best friends for 6 years, and we continue to be. We, like many others before us and many after us, grew in different directions over those same 6 years.”
“Kaitlynn is a wonderful person, beautiful and fun to be with, always a positive force in my life,” he continued. “We decided the best move for both of us was to keep our love for each other strong but move forward separately with our lives. I respect Kaitlynn and care deeply about her. She deserves to be able to move forward in her life with respect and happiness.”
As for Carter and Cyrus? A source recently told PEOPLE they “live together and are very happy.”
“Miley is doing great,” said the source. “She is moving on. She seems to have no regrets. She loves being with Kaitlynn.”
Jenner has also moved on: PEOPLE recently confirmed that the DJ is dating 22-year-old model Josie Canseco.
The Hills: New Beginnings airs Mondays (10 p.m. ET) on MTV.