"It's just time to throw in the towel," the Bravo reality star tells the camera on Monday's "Vanderpump Rules."
But the breakthrough came at the expense of his ride-or-die girlfriend, Brittany Cartwright, who's stuck by his side all season long even though he admitted to cheating on her with one of her now-former friends from SUR.
In a one-on-one conversation on Monday night's episode, Jax told Brittany he's been "unhappy for such a long time." Brittany, of course, took offense considering she's been dating Jax for over 2 years.
"You're making me feel like shit right now," she said. "How are you making this about you?" he replied.
Jax reassured her his unhappiness had "nothing to do with" her, but he followed it up by suggesting they break up.
"You deserve to be happy. You deserve to get married. You deserve to have kids," he told her. "You deserve to have someone treat you like the princess that you are, and I just am not that person."
Brittany's face dropped. "So what're you saying?" she asked.
"I am not good in relationships," he replied. "You deserve a lot better than me. I just don't think we can be together anymore."
Brittany struggled to understand what exactly Jax was saying, but he reiterated it loud and clear. "I'm not happy with myself!" he shouted.
"I don't like who I am, and it's not because of you," he said tearfully. "Look at all this shit that I've caused this summer. Look at everything."
"How can you do this to me when I've been through so much and I'm trying to help you and trying to work on things with you, and now all of a sudden you're gonna say that you [don't wanna be with me]? Why have you let me try and go through all this pain?"
"It's not working," Jax said before telling Brittany he needed to "be alone."
"How dare you do this to me?!" she shouted, ordering him to leave their apartment. "How dare you put me through all this shit and let me go through all this heartbreak, and then for you to sit here and just act like you're the one to give it all away! We were just fine, and now all of a sudden, you wanna break up? After everything I've been through? This is bullshit! This is complete bullshit."
Jax later told Bravo cams, "I really respect Brittany so much that she stuck around and tried to make things work with me, but I'm tired of seeing Brittany upset and sad, and I think it's just time to throw in the towel."
"Vanderpump Rules" airs Mondays at 9 p.m. on Bravo.