In season six, episode nine of MTV's "Teen Mom 2," Leah Messer rushed home from therapy on a threat of losing custody of her twins, Aubree wanted to call Chelsea Houska's boyfriend Cole DeBoer "dad," Jenelle Evans' ex-fiancé Nathan Griffith moved on with another girl, and Kailyn Lowry and Javi Marroquin got into an argument over Lowry's ex-boyfriend Jo Rivera.

Leah Messer left her twin girls, Ali and Aleeah Grace, with her ex-husband Corey Simms while she sought therapy for depression at a rehab center. However, when Messer's mother Dawn dropped the girls off with Simms, he made statements that worried Dawn. She called Messer immediately, and Messer hopped onto the next flight back home, concerned that Simms would try to file for abandonment and get temporary full custody of the twins. Her lawyer was able to sort out an agreement with Simms' lawyer, and she planned to return to rehab the following week. Simms spoke with Messer and assured her that the custody threat was a misunderstanding and that he supported her decision to seek treatment.

"We want what's best for you and we want what's best from them," he told her. "We would never do nothing to take them from you."

Chelsea Houska's boyfriend Cole DeBoer is moving in soon with her and her daughter Aubree. DeBoer already took on the role as Aubree's stepdad and even attended her pre-kindergarten graduation ceremony, which made things awkward for Houska's ex-boyfriend, Aubree's biological father Adam Lind. During a lunch date with her friends, Houska revealed that Aubree wants to call DeBoer "dad" once he moves in and explained why.

"She said thinks he's like a better dad, which I didn't tell her that," Houska said, "and she said that her dad was in jail."

"Two times," Aubree said.

Jenelle Evans had a hard time accepting that her ex-fiancé Nathan Griffith moved on so quickly. After two years and one child together, Griffith decided to break things off with Evans after he was arrested on state domestic violence charges stemming from a fight between them. Griffith's charges were dropped, and Evans finally allowed Griffith to spend time with their 1-year-old son Kaiser. Griffith wanted Evans to pick up their son, but she wouldn't give him a straight answer. He showed up at her housing development and Evans drove off, with Griffith weaving in and out of traffic as he followed her, calling her cell phone. Evans finally answered Griffith's call and explained why she didn't want to pick up Kaiser.

"You're hurting me, this is why I didn't answer," she said, crying. "I can't do this anymore with you, it hurts my feelings, I'm going f---ing crazy dude."

Kailyn Lowry just started to adjust to her ex-boyfriend Jo Rivera as a neighbor after he moved into the same housing development to be closer to their son Isaac. But she got into a fight with her husband, Javi Marroquin, when he learned that Lowry let Rivera into their home when he wasn't around.

"I don't want him at my house if I'm not there, point black," Marroquin told Lowry. "You never know what can happen when I'm not there. It's my house, I don't want him at my house and that's it."

Watch a clip from the episode below.