Teen Mom 2 The cast of "Teen Mom 2:" Jenelle Evans, Kailyn Lowry-Marroquin, Chelsea Houska and Leah Messer Calvert.

When we left “Teen Mom 2” star Leah Calvert on the series Season 5 finale Wednesday night, the reality-TV star was still battling her ex-husband Corey Simms for custody of their twins, Ali and Aleeah, 4. While the latest details regarding the duo’s new custody arrangement won’t be announced until their next hearing on Dec. 8, new reports are surfacing claiming that Corey, 25, is planning to use Leah’s drug use, a storyline featured on the series, against her in family court in an effort to secure primary custody.

Leah, who tearfully admitted to feeling like a "druggy" on the program after taking anxiety medication in order to help combat the stress of raising their special needs daughter Ali, has Corey concerned about his daughter's safety while in the “Teen Mom 2” star’s care, In Touch Weekly (via Radar Online) is reporting. “Corey has made it clear that [he] will stop at nothing to win this case,” an insider said. With less than three months until their next court date, insiders said that the 22-year-old mom of three (she is also mom to daughter Adalynn, 14 months, with husband Jeremy Calvert) is fearful that Corey’s allegations may put her at risk of losing primary custody. “Leah is terrified that Corey is going to portray her as a drug user in court,” said a source.

Leah’s alleged pill popping is not Corey’s only concern. The MTV star is reportedly uncomfortable with Leah caring for Ali who requires the use of a wheelchair due to her rare and incurable form of muscular dystrophy. “Corey believes he’s in a position to provide more stability and consistently than the children are receiving now,” Corey’s Kanawha County, West Virginia-based attorney, Rusty Webb, said.

In Touch Weekly last reported about Leah’s alleged drug use in September, stating that Corey only filed for full custody of the girls in an attempt to get back at Leah for requesting more child support. “A few months ago, Leah asked Corey for more money and it really pissed him off,” said an insider. “He knows that [Leah] is a good mom.”

On recent episodes of “Teen Mom 2,” Corey slammed Leah for missing two of Ali’s physical therapy appointments, putting his daughter at risk of losing her medical insurance. Leah rebuffed his claims on Wednesday’s finale.

“I’ve been there with the girls since day one, I’ve done everything I possibly can for them, I am a stay at home mom, that’s all I know,” Leah tearfully told Corey. “You doing this, it’s like you would be stripping my whole life away from me."

Leah and Corey, formerly of “16 and Pregnant” fame, divorced in 2011 after just six months of marriage. Corey remarried homemaker Miranda Patterson in June 2013. Leah and Jeremy, a pipeliner, tied the knot in 2012.

The “Teen Mom 2” reunion airs Tuesday at 10 p.m. EDT on MTV.