On the season premiere of Welcome to Plathville, we learned that Moriah Plath had split from Max Kallschmidt.

On this week's episode of Welcome to Plathville, we'll learn why.

Kallschmidt and Plath had been a romantic tem for more than a year when they split towards the end of 2021... not long after the former gave the latter a promise ring during the show's third season -- and also planned to move to Tampa with her.

On the May 17 return episode, Moriah was distraught.

In an attempt to lift her spirits, Ethan and Olivia Plath invited Micah Plath for a visit around Thanksgiving.

When Micah asked his sister what happened with Max, she simply broke down in tears.

Cut to a sneak peek at the May 24 installment of Welcome to Plathville, posted by People Magazine, and Micah confronting Kallschmidt about where everything went wrong.

"I f—ed up, man, pretty bad," Max begins, immediately breaking down himself and then delving into quite an explanation of events:

"I have this good buddy of mine that's a good bit older than you and I.

"We used to work together and we were kind of celebrating his retirement at his place and he invited his lady friend over that I knew he liked. And so I was trying to be his wingman.

"And so I took things a little too far. I was just flirting with her, and that led her to think that it was okay to try and kiss me, which she did."

YIKES, huh?

"I told Moriah, like, 'Oh, this happened,' and, like an idiot, I said, 'I'm proud of myself for not letting it go too far,'" Max continued in this chat with Micah, adding:

"She broke up with me, which is reasonably so."

We'd have to agree. Even if you believe this version of events (which, let's be honest, feels like a stretch), we understand why Moriah would end things in response.

"The biggest emotion I felt while he was telling me what happened was anger," Micah admitted in an interview after the conversation.

"Now it's not only betrayal on Moriah's part but also the friendship that we had. Most of us didn't think he was capable of that."

In condescending fashion, Kallschmidt also asks Micah to be there for Moriah -- which, d'uh, of course he will be. We're talking about his sibling here.

"Uh, yeah, I love Moriah. She's the sister I'm closest to and anytime she gets hurt, I get hurt too," Micah tells Max. "And I will say I'm really f—ing disappointed in you."

Kallschmidt wasn't even done confessing to his sins, either.

"After all of this, we kind of like just took a real hard reflection on our relationship, and we dived into the clothes that she wears, and then that just kind of made me pissed off and in my anger, we just erupted into a big argument," Max went on.

"I definitely said some things that were hurtful...

"I want to do better."

On the aforementioned season premiere, Moriah hinted that infidelity played a role in the end of her romance.

"A couple weeks after I moved to Tampa, Max called me one night and just said he made a mistake," she said in a confessional. "I'm not going to go into details. Since then, I have been in a dark place."

"I'm scared to share what happened with anybody because if I say it out loud, it becomes real," she added.

Welcome to Plathville airs Tuesdays at 10/9c on TLC.