Jax Taylor 'Went Berserk' After Finding Out Estranged Wife Brittany Cartwright Secretly Hooked Up With His Pal Julian Sensley Post-Split: Source

Insiders are spilling more tea about what went down behind closed doors after Brittany Cartwright and estranged husband Jax Taylor separated this February.

The exes are going through more drama than meets the eye, as a source has revealed the mom-of-one started secretly hooking up with Taylor's pal Julian Sensley after their split.

According to the source, Sensley, 42, and his "off and on" fiancée were "going through a rough time" when the former NBA player started seeing Cartwright, 35. Sensley shares one child with his fiancée and and older child with an ex.

Though the former Hooters waitress' fling with Sensley — who used to work at Tom Schwartz and Tom Sandoval's bar TomTom — is now over, the insider admitted Taylor, 45, "went berserk" when he found out about the romance.

The source noted that the drama between the estranged spouses, who share son Cruz, 3, will play out on Season 2 of The Valley.

Taylor hinted at the tryst in June when he wrote in a since-deleted tweet, "you may want to ask Brittany who she’s been sleeping with for the past 4 months…."

As OK! reported, several months after the exes parted ways, Taylor entered a mental health facility, where he was diagnosed with PTSD and bipolar disorder.

"I’d be lying if I said I wasn’t scared for the future but my focus is just trying to be a better version of myself than I was yesterday," he told fans via social media. "Mental health is a lifelong battle of not letting it control you but rather you learning to control it."

Despite finally getting help with his demons, Cartwright filed for divorce in August after five years of marriage.

On a solo episode of the stars' joint podcast, "When Reality Hits," the Kentucky native said her decision "wasn’t made lightly or quickly."

"I never imagined I’d go through something so personal and painful while having the world watch," she added. "I’m not saying this for anyone to feel badly, but I know that this is the life I chose and I’m so fortunate in many ways. I always want to be real with y’all."

Though the Vanderpump Rules alumni were co-parenting throughout their separation, Taylor shockingly asked for Cartwright to have full physical and legal custody of their tot — however, shortly after he filed the documents on his own, he had to refile due to several errors, including his mistake of checking a box that claimed the duo was never married.

A rep for Taylor recently told a news outlet, "Jax and Brittany have already long resolved all matters related to custody of Cruz and will continue to work together privately for the best interest of their son, which remains their overriding concern."

Page Six spoke to the source about Cartwright's fling.