Things are going to get ugly for "Teen Mom 2" star Jenelle Evans. In a new sneak peak clip for Thursday night's episode, Evans and her fiancé Nathan Griffith are fighting once again. Tempers are mixed with alcohol, and the result is disastrous.

What the fight is about is not clear in the clip from Us Weekly, but it seems as though Griffith thinks Evans is cheating on him. The clip starts out with Griffith pouring alcohol into a cup as he yells at the woman he wants to marry. "I f--king caught you!" he screams at Evans while he pours himself a tequila on the rocks.

"You're paranoid," Evans replies. "I haven't talked to anyone. I've been completely faithful. You saw my phone as soon as I came home."

The former Marine keeps shouting, "You've got problems! I've been to war and back, and you've got problems," he angrily says.

"And that's why you've got problems," Evans responds, referring to his time in the military. "You need to go to counseling. You need to seek some medication."

She tries to reason with Griffith at first but gives up and pushes the bottles of liquor closer to him. "Drink some more, buddy. You've almost finished them. You're a champ. Drink all of them. That's all you ever do," Evans tells him.

"You're f--king trailer trash who hit the lottery. End of story. You're nobody special. You're stupid. You're just stupid, dude. You're not on the same caliber as I am," Griffith finishes.

The couple is no longer together after ending their engagement for the second time earlier this month, according to Entertainment Tonight. The next episode of "Teen Mom 2" airs Thursday, Aug. 13, at 10 p.m. EDT on MTV. Watch the clip of the two duking it out below.