"I just expected you to do the right thing instead of run the town with your single boys," she says.
But when Austen claims their problems really stem from Madison's lack of "compromise," the situation quickly escalates.
"Don't you ever say the word compromise because you are the last person to compromise on anything," she says. "We're just two people on two different paths. You're going a-- backwards."
"Do I want to have a six-foot-five grown a--- man on my back treading water for the rest of my life?" she says, which leaves Austen speechless.
Holding back tears, Madison ultimately decides to end their relationship.
"I've tried so hard to make this work, over and over again," she says. "But there are some times when you hit that f---ing wall you can't move past. And I feel like we hit it."
"That's a f---ing shame, because I wanted to be with you," she adds.
Clearly distraught, Austen admits he's not ready for things to end.
"I hear what you're saying Madison. I just don't know how to let you go," he says.
Austen, 33, and Madison, 31, have had a whirlwind relationship over the years, often breaking up and then coming back to each other. Last November, he opened up about the on-off romance during the Southern Charm cast panel at BravoCon, saying the two were "doing well" at the time.
"This week I'm doing well with Madison," he said last year. "Maybe next week that will change, but I'll let y'all know."
"We've tried to go our separate ways," he added. "Madison has been a person for me for a long time and it's really tough to walk away from something like that. She's a hell of a woman and I find it hard to walk away from."
Southern Charm airs Thursdays (9 p.m. ET) on Bravo.