Maci Bookout and her ex-fiancé Ryan Edwards have come a long way in their co-parenting relationship with their 7-year-old son Bentley on this season of MTV's hit reality series "Teen Mom OG." In a sneak peek for part one of the reunion special airing tonight, Bookout opens up about how she feels about Edwards' new girlfriend and her influence on Edwards' parenting.

In a one-on-one with reunion special host Dr. Drew Pinsky, Bookout and Edwards elaborate on their rocky past relationship and their struggle with co-parenting Bentley. Bookout says because the exes know how to trigger one another, all of their past attempts at co-parenting would result in fights.

"We were both really scared to be around each other and communicate with each other because, for so long, any time we were around each other or any time we did have to communicate, it always turned into an argument," Bookout explains to Pinsky. "And I think we both realized if we're gonna get past this we have to face it. We can't just keep avoiding each other because we're scared of arguing. Like, what do we have to argue about?"

Both parents agree that their son Bentley has inspired them to work harder on their relationship and the way they communicate with one another. But when Pinsky asks Edwards about his new girlfriend, Edwards gets uncomfortable and skirts around the questions. Pinsky turns to Bookout instead.

"In the past, you've always been worried when Ryan gets a girlfriend. His attitude goes against you a little bit. This one's different," Pinsky tells Bookout.

"Well, honestly, I just met her today, but she's really really cool," Bookout says. "I can already tell she's much different from previous girlfriends."

Watch the full sneak peek below and be sure to catch part one of the "Teen Mom OG" reunion special airing tonight at 10 p.m. ET on MTV.