Amber Portwood’s got a new man, and her ex-fiancé, Matt Baier, doesn’t seem to be too thrilled with the news! The Teen Mom OG star was recently spotted smooching Andrew Glennon, a producer from Marriage Boot Camp — aka the show the former couple went on earlier this year in an attempt to save their engagement.

A source told Radar Online, “Matt knew she had a new guy, but didn’t know it was Andrew.” They added, “Now he is furious and suspects her of cheating on him.” Amber, however, is denying the claims. “Amber thinks Matt is just jealous,” said the source.

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Amber and Matt at the 2015 MTV Movie Awards.

The pair first met on Twitter, and things quickly became serious after he moved in with the 27-year-old almost immediately and proposed just months later. While they had their ups and downs, they officially called it quits after he failed a polygraph test when asked whether he had ever cheated on Amber.

The reality star recently took to Twitter to defend her new romance. She tweeted, “There’s nothing wrong with dating over three months after breaking up with someone… Crazy how people judge and are so quick to talk s–t.” She also addressed their age difference — since there was a 15 year age gap between her and Matt. “He’s 33?? I’m 27…that’s perfect to me and that’s all that matters,” Amber wrote back to a curious fan.

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Meanwhile, seeing Amb with someone new prompted the former reality star to reflect. He recently revealed to E! News, “I’m trying to do a lot of work on myself because I realize now the downfall of our relationship was my fault,” he explained. “When you’re thrust into the spotlight like that, it can affect you. My mistake was taking our relationship for granted.” He added, “What I’ve learned from this is you have to do the work. You have to make the person you’re with feel loved every single day. I forgot to do that, and now I’m paying the price.”

So does that mean that if he got a second chance with the mom-of-one, he would do it? “If I got a do-over,” he said, “I would do everything differently. I should have listened to her more.” Unfortunately for him, she seems smitten with her new man — and TBH, we think she’s better off. Sorry, Matt!

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Scroll through the gallery below for photos of Matt and Amber’s tumultuous relationship!