Ronnie's Ex Confirms She Cheated ... But Says He Did Too

Now, Jen's giving her side of the story.

"I'm sure he's referring to when we were dating for about a month or two," the new mom told Us Weekly following the episode. "We hadn't established a real relationship. My ex came back around. I had mixed feelings at the time. We just got out of a 4-year relationship."

As documented on the MTV "Jersey Shore" revival, Ron and Jen's love story has never really been easy peasy. In fact, right around the time she gave birth, the two got into an explosive fight on Instagram, which Jen revealed stemmed from her messy relationship with her ex.

"This is all part of the Instagram fight we got into because of this incident," she said. "When I came clean about this, he came clean about three times he hooked up with other girls in the same time period. We decided we wanted to be together and work though this and not to ever do it again."

During the fight in question, Ronnie posted the following message to his Instagram Story: "Note to self: Can't turn a natural-born HO, into a HOUSEWIFE. If you find them in the gutter, leave them in the gutter." He followed that up with another post that read, "If your significant other keeps sex videos of their ex, shouldn't they show enough respect to delete them, esp. after being in a new relationship for over a year?" he asked, along with a Yes/No poll for fans to vote.

Jen responded to the craziness with an Instagram Story of her own, writing, "Can't turn a coke head into a father!" She followed that up with another post that read, "When your man goes all Rob Kardashian on you," accompanied by a laugh-cry emoji.

All the posts have since been deleted, but we have the receipts here.

Conveniently, Ronnie made sure to leave out the part of him also hooking up with other people when he told Nicole "Snooki" Polizzi, Jenni "JWoww" Farley and Deena Cortese on Thursday's episode that Jen was untrustworthy.

"I'm just more worried about me and Jen, to be honest with you," Ronnie said to the girls. "I don't know where we stand. I mean, we're together. I wanna be with her, I love her, I just don't know where her heart is."

"Did you talk to her at all?" Jenni asked.

"I mean, obviously she's gonna say I love you and I wanna be with you, but it's like, truthfully, I just don't trust her," he said. "So I'm worried about what happens after the baby."

"Like you're nervous she's going to cheat on you?" Deena asked. "Yeah," Ronnie replied.

"Because she did before?" Nicole asked. "Yeah," he said.

"We're good right now, you know? But I don't know if it's because she's pregnant," Ron said, adding that he was scared she'd "go back to her old ways" after giving birth.