After revealing the real story behind Flip or Flop stars Tarek El Moussa and Christina El Moussa’s explosive divorce last month, In Touch has learned even more shocking details of the couple's troubled marriage. An insider reveals that Tarek hired a private investigator to watch wife Christina last year when he suspected she was seeing someone else.

MORE: Tarek El Moussa Spotted on Date With Mystery Woman

“When he and Christina were on the rocks, he confessed to the production crew that he suspected she was dating some­one, so he hired a private investiga­tor to follow her. He wanted to know where she was going and what she was doing,” the insider explains.

The insider adds that Tarek suspected it was Gary Anderson, a contractor who used to be his friend and even redid the couple’s pool last year be­fore their breakup.

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“It’s hard for Tarek to see Christina dating, but it’s even worse that Gary is the guy she’s with."

In Touch recently revealed the first photos of Christina flaunting her hot new romance with Gary.

“It stings, and Christina knows it,” says the source. “Tarek is incredibly jealous and filled with rage.”

MORE: Tarek and Christina Make First Joint Appearance After Divorce Announcement

As In Touch has reported, Tarek did many horrible things to his wife Christina over the course of their seven-year marriage — including calling her horrible names, berating her, and making her cry on the set of their HGTV series.

Christina hasn't publicly denied that Tarek treated her like garbage. She told In Touch through her rep that she would "not be providing any comments” about Tarek’s behavior.

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