HGTV personality and mother-of-two Christina El Moussa has been flaunting her hot new romance with Ant Anstead every chance she gets — and ex-husband Tarek El Moussa can’t take much more. "He’s all smiles publicly, but behind closed doors he is extremely bitter that Christina has found love," a source tells In Touch.

The pair, who had a nasty breakup in 2016, have reunited to film an eighth season of their hit HGTV show, Flip or Flop, and tensions are reaching a boiling point. "They’ve been bickering about anything and everything," says the source. "There’s definitely been a change in Tarek’s behavior toward Christina."

That’s because he knows that his ex-wife, 34, has real feelings for the British TV presenter, 39. "He sees how in love she is and how natural they are together," says the source, adding that Tarek, 36, is also upset that a back injury has stopped him from hitting the dating scene. "He’s consumed with jealousy!"

Christina and Ant's relationship has been moving rather quickly since they first began dating this year. Not only is he "fantastic" with her two kids — daughter, Taylor and son, Brayden — but In Touch exclusively revealed in April that they're talking marriage. "She loves his down-to-earth personality. He's a TV star but he's very low-key and isn't into the glitzy showbiz lifestyle," said a source.

Tarek, on the other hand, hasn't had much luck in the dating department since splitting from his wife in December 2016. In Touch revealed in January that he was "in love" with lingerie model Patience Silva after meeting her on the dating app Raya — and before that, he was involved with his kids' nanny, Alyssa Logan. Hopefully he finds love soon — at least for Christina's sake!

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