Expect more drama between Leah Messer and her ex Corey Simms on next week's "Teen Mom 2." Simms meets Messer's mom in a parking lot to pick up his twin daughters, Aliannah and Aleeah Simms. When Messer's mother mentions taking the girls to visit their mom on Mother's Day at the rehab facility, he gets upset.

"What day do you want me to pick them up this weekend -- except for Mother's Day, I'm going to take them to see their mommy," Messer's mother asks Simms in the video clip, after he loads his daughters into his car.

Simms asks where she will be taking the twins to see his ex-wife.

"I'd really rather not disclose that, Corey," she says.

"I really don't want my kids going somewhere I don't know where they are," he says, as if implying that she -- the twins' grandmother -- cannot be trusted with their safety or whereabouts.

Messer's mom calmly defends her position that the girls should visit their mother on Mother's Day, but Simms counters with a lame argument that it was Messer's decision to go.

"I did not make this decision for her. Neither did her children. She left on her own free will, knowing that she was leaving her children for a month. Now that I have them, I am their parent. I have to make the decisions on my own," he says.

The video clip ends with Messer's mother looking disappointed, to say the least.

In another video clip for the next episode, Jenelle Evans calls former boyfriend Nathan Griffith to ask if he can pay for a week of daycare for their son. Evans quickly changes the conversation from childcare to their relationship; telling him that she wants to get back together and that it is "so hard for me to keep calm when there's another girl."

Evans falls to pieces as she tells him how much it hurts that he has moved on so fast.

"I have not touched another man's skin for two years," she says, tearing up.

Griffith explains that that he had a 5, 10 and 15 year plan in his head for their life together, but that they are not a good match.

"We were killing each other -- literally killing each other," he says, and the sneak peek ends.

Meanwhile, Chelsea Houska's daughter Aubree is totally obsessed with her mother's boyfriend Cole. In the next episode, Aubree reveals to her mom's friends that she has a nickname for the man in her mom's life: daddy.

Jo Rivera and Kailyn Lowry sit down to discuss plans for their son Isaac. Rivera's response to Lowry's concerns will surprise you.

Watch "Teen Mom 2" Season 6 Episode 9 on Thursday, Sept. 3, at 10 p.m. EDT on MTV.

Do you agree with Simms' decision not to allow his daughters to visit their mother in the rehab facility on Mother's Day? Do you think Evans and Griffith's break up is a good thing? Share your thoughts in the comment section below.