Uh oh. Selena seems to finally be moving on from Justin Bieber, but the ‘Baby’ singer isn’t happy about it, a source tells HollywoodLife.com EXCLUSIVELY. And it’s because Zedd, the DJ/producer, Selena’s been packing on the PDA with, is a mutual friend of theirs.

Justin Bieber thinks Selena Gomez is purposely dating Zedd, a mutual friend of theirs, in order to push his buttons and get back at him. Whether or not Selena has ulterior motives, she seems to be happy with this other man, which makes Justin “furious,” HollywoodLife.com has EXCLUSIVELY learned.

Justin Bieber ‘Furious’ Selena Gomez’s Dating Zedd — It’s A Slap In The Face

“Justin is furious that Selena is dating Zedd. He was Justin’s friend first and it’s just not cool that she’s with a mutual friend. Justin thinks this is Selena’s way of getting back at him,” a source tells HollywoodLife.com EXCLUSIVELY.

Justin Bieber & Selena Gomez: Awkward Run-In At Cody Simpson’s Birthday Party?

Justin and Zedd worked together when producing their 2012 hit, “Beauty And A Beat.” So it’s pretty obvious that Justin and Zedd have a history together. And Selena’s taking full advantage of Zedd’s capabilities. Not only is she dating Zedd, but they’re working on new music together.

Selena Gomez & Zedd: Working On New Music Together

“What really infuriates Justin is Selena’s song collaboration with Zedd. He feels like this whole thing is just a slap in his face. He was the one who was suppose to collaborate with Selena on a song, not Zedd. To the outside world, Justin is going to act like he doesn’t care one bit, but in his inner circle, everyone knows he’s hurting big time over the fact that Selena is with Zedd,” our source says.

Poor Justin. We can’t imagine any of this is easy. But he’s dating Hailey Baldwin now, so he should be happy for Selena. They should both be happy for each other.

What do YOU think, HollywoodLifers? Is it wrong to date an ex’s friend? Do you think Justin should be worried? Tell us how you feel!

— Chris Rogers, Reporting by Sandra Clark

Follow @ChrisRogers86