As the cast reunited in Atlantic city to celebrate Pauly "DJ Pauly D" DelVecchio's birthday, the news that Harley would be joining them had the other cast members on the edge.
"Ron and Jen's relationship has been very toxic the past couple of months," Mike "The Situation" Sorrentino told the cameras, referring to the car incident that made headlines earlier this year. "We've all seen it. Big Daddy Sitch would have to predict that this trip just gets crazier as the days go on."
Ronnie insisted that he and his girlfriend had made amends since the incident, but Jenni "Jwoww" Farley was not convinced; comparing the situation to Ronnie's past relationship with Sammi "Sweetheart" Giancola.
"At the end of the day, I know Ron will never leave a girl," she said. "He cannot be the one to walk away. Sammi is the one that had to leave, and I ultimately think Jen will be the one that has to leave."
Later in the episode, Jen arrives to Atlantic City with the baby and Ronnie and Jenny head out to dinner with the gang, as PEOPLE first reported.
"I love that Ariana and Jen came to visit," he said. "I just want [the roommates] to see Jen the way that I see Jen, see the person that I fell in love with, the person that's funny and likes to have a good time and is just like me. I love her and I want everyone to see why I fell in love with her. I hope my roommates love Jen as much as I love Jen and we can be one big happy dysfunctional family."
Dinner did not go so well, as Jwoww made a joke about Jen's mugshot to break the ice, leading Jen to apologize for her actions.
"I know everything sounds so psycho and crazy, but both of us signed up for anger management," Jen said. "We're trying to take the steps to not be crazy anymore."
The conversation seemed to lead to an understanding between the roommates and Jen, though they were certain to "never forget" what had happened in the past.
The calm did not last long as when the group was at the club, Ronnie and Jen got into a drunken fight when he tried to stop her from taking another shot.
"The hard thing about being with Jen and drinking with her is that she's fun and we have a good time, but she doesn't know her limit," Ronnie said. "She doesn't know when to stop. She doesn't know how to be rational when she's intoxicated, and I think that's where our disconnection is."
The moment led to a heated argument where the couple screamed insults at each other repeatedly, angering the group of friends who were not really surprised by the turn of events.
Later, Vinny tried to talk to Ronnie about his relationship, wondering why he is still with her.
"At this point, I don't know what to think with Jen. How much more can I deal with someone that's irrational, doesn't want to listen, gets angry, vulgar — it's becoming too much," Ronnie said. "She just gets in a f—ing mood where it's like, she's uncontrollable. And that's where I learned I've got to walk away, because if I try to fight it she gets crazier and crazier. It just can't keep happening. It's consistent with her."
"But you know that, though," Vinny said. "Bro, you can't deal with that s—. It's so frustrating. And I feel bad for you, because now you're like, in this f—ing limbo period where you're like, 'Where the f— is our relationship, where is my baby?' I f—ing hate that. If you truly didn't do anything tonight and she just did this s— out of nowhere, I hope that you just add this to your list of why possibly she has issues."
Ronnie looks visibly upset by how the events of the weekend went down, though he is still in a relationship with Harley despite serious red flags to this day.
Jersey Shore Family Vacation airs Thursdays at 8 p.m. ET on MTV.0comments