Nathan Griffith and Jenelle Evans Credit: Todd DC/Splash News

Tensions are high between Jenelle Evans and ex-fiancé Nathan Griffith. The star of Teen Mom 2 exclusively reveals in the latest issue of Us Weekly that her nearly yearlong fight for custody of their son, Kaiser, 20 months, is still unresolved.

"I'm trying to file custody papers, but Nathan won't give me his address,” claims the North Carolina native, 24. "If he's going to have Kaiser for a weekend, I need to know where he is."

Though Griffith, 28, has accused Evans on Twitter of not letting him see their son, the mom of two, who also has son Jace from another relationship, insists the claims are false.

"He hasn't asked to see Kaiser since December," Evans tells Us. "He tweets about me but he won't text me and ask to see him.… He wants to make me look bad."

Evans and Griffith, whose tumultuous and violent on-and-off love affair has dramatically unfolded on the MTV series, got engaged in January 2015, but called off the wedding in July of that year.

Evans, now dating David Eason for six months, is also hoping to regain custody of her eldest son, Jace. The 6-year-old has been living with his grandmother, Evans' mother, Barbara, but Evans will try to win him back at a May 3 hearing.

"I'm asking for full custody," says the reality star. "I see Jace every weekend. There's no reason why I shouldn't have him full-time.… My mom hasn’t budged at all, so I'm just going to have to let the judge decide."

For her part, Evans thinks her new relationship with Eason, 26, who has a 6-year-old daughter, may help her case: "I think my mom is more accepting of me dating someone that is good. She really likes David a lot."

Although a trailer for the upcoming season shows Barbara calling Eason "the worst boyfriend” her daughter has ever had, Evans explains that, for the most part, the two are amicable. The reality star tells Us her mom appreciates the quality time Eason spends with Jace, and has even thanked him for it.

Teen Mom 2 returns to MTV Monday, March 21, at 10 p.m. ET.

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