On tonight's Teen Mom OG, Amber Portwood's ex-fiance, Gary Shirley, drops a major bomb about her current fiance, Matthew Baier.

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After Portwood initially refused to get out of the car while exchanging their daughter, Leah, Shirley eventually lured her onto his porch, where he presented her with shocking documents regarding Baier.

"I don't know if you are aware.. This is coming up... Do you know how many kids he has?" Shirley asks his ex in a sneak peek at tonight's new episode.

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"Yeah, two," Portwood responds, prompting Shirley to show her proof of otherwise.

"He has seven. Matthew," Shirley points out.

"That's not his kids. These are his kids right here," Portwood insists, claiming she's talked to his exes and is well aware of how many children he's fathered.

However, Shirley presses on, claiming Baier is being taken for child support.

"They are hitting him for child support right now, and four or five of the kids have 'Baier,'" Shirley continues. 

Still, Portwood isn't convinced that her fiance has been keeping children secret, and tells Shirley that if his child support claims were true, he would have been thrown in jail long ago.

"I've been with this man for over a year, I think I know him," she says.

But apparently, she doesn't. As The Ashley's Reality Roundup revealed weeks ago, Baier appears to be the father of seven children, and also has one grandchild, and one on the way.

For more of Amber Portwood, Gary Shirley and her fiance, Matthew Baier, tune into Teen Mom OG tonight, Feb. 1, at 10 p.m. on MTV.