And to make the already complicated situation even more interesting, Tarek has apparently taken a literal liking to his ex-wife's ex-husband, Ant Anstead.
Evidently, they have more in common than marriages to, children with and divorces from Haack.
As Radar previously reported, Tarek is engaged to Selling Sunset star Heather Rae Young, who's friends with media personality Jessica Hall, who's the sister of Christina's current boyfriend, Joshua Hall.
As for Ant, he's currently dating Renée Zellweger.
The two just attended their first public event as a couple, prompting Anstead to make their relationship IGO (Instagram official).
The car aficionado and Oscar-winning actress looked head-over-heels for one another at last weekend's grand gala held at the Lyon Air Museum in Santa Ana, California, hosted by Radford Motors to celebrate the unveiling of the new Lotus Type 62-2 race car.
Ant was one of three people who'd been working to revive the Radford Motors coachbuilders brand, so in addition to having a star on his arm, he was a star himself that night.
Tarek also documented the posh evening, even sharing some videos of Ant's unveiling and tagging the English TV personality on his Instagram Story.
Of course, his fiancée made it to the actual feed. "Last night," he captioned a photo of the dashing couple posing outside before the party. "A night out filled with friends, cars, and my love @heatherraeyoung… no complaints here. What'd everyone do this weekend!?"
Tarek has actually been gushing over Ant and Renée's romance since last month!
"I love it! I love it! Good for him," he told People. "Ant's a great kid, [Zellweger] seems like a lot of fun. I like them. I like the setup."
No word on how he feels about Haack's new man, but after she told the whole world that she met Hall following a psychedelic trip from smoking a Bufo toad, El Moussa reportedly went off on his ex on the set of their joint HGTV show, Flip or Flop.
Tarek and Christina were married from 2009 to 2018 and share two children: 10-year-old daughter Taylor El Moussa and 5-year-old son Brayden El Moussa.
She went on to marry Ant in 2018, with the two finalizing their divorce earlier this year. Together, they have an almost-2-year-old son named Hudson Anstead.