Jenelle Evans and her ex- fiancé Nathan Griffith have always had a volatile relationship, and things between the two are even worse now that Griffith has a new girlfriend. In a sneak peek for the March 28 episode of MTV's "Teen Mom 2," Evans is furious when she finds out that Griffith allowed his new girlfriend to give their son Kaiser his first haircut.

During last week's Season 6 premiere of MTV's hit reality TV series, fans got a first glimpse at Griffith's new girlfriend Jessica Henry - and learned that Evans is facing assault charges stemming from an altercation with Henry. Griffith brought Henry to Evan's home to gather his belongings after their break up and Evans allegedly threw a drinking glass at Henry's head.

In the clip from tonight's episode, Griffith returns to Myrtle Beach, S.C., from a trip to Boston and Jenelle brings her friend Tori along with her to pick up little Kaiser from Griffith's mother.

"I'm so mad," she whispers to Tori as she buckles Kaiser into his car seat. "Jessica cut his f--king hair. Look at his bangs."

Fuming, Evans closes the back door and gets into the drivers' seat.

"Cut my f--king child's hair," she spews. "Really?"

"How do you know she did it?" Tori asks calmly.

"She's a f--king hair stylist, Tori," Evans explains. "I am so heated right now."

Evans pulls out of the parking lot and drives off, calling Griffith on speakerphone.

"So you want to take it upon yourself to have Jessica cut Kaiser's hair?" she asks as soon as he picks up the phone.

"No?" Griffith says slowly.

"Who cut his hair?" Evans responds. "Like this is insane, and you know what? I'm changing my number right now and if you want to see Kaiser, you can take me to court for visitation. Goodbye."

She hangs up the phone on Griffith and continues to vent to Tori.

"That's his first haircut and I want to be there for it," Evans says, explaining why she's so upset. "And I want to take pictures and everything."

Watch the full sneak peek below and be sure to catch tonight's episode of "Teen Mom 2," airing at 10 p.m. on MTV.