Scott Disick and Kourtney Kardashian are having serious issues as co-parents.

The exes, who dated on and off from 2006 to 2015, appeared to be in good spirits lately as they raise their three children: Mason, 11, Penelope, 8, and Reign, 6. That no longer seems to be the case.

“What’s really got him riled up is the effect Travis [Barker] and Kourtney’s relationship is having on his relationship with Kourtney,” a source told Us Weekly.“It’s more strained than ever.”

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Barker, 45, and Kardashian, 42, started dating in January. Disick, 38, allegedly takes issue with how much the celebrity couple packs on the public displays of affection and how it may affect the “KUWTK” stars’ children.

“He’s trying to be the best parent he can be for their kids and make it work co-parenting, but he’s having problems now with Kourtney,” the source explained.

“He doesn’t think she should be showing off too much PDA because of their rated-R behaviour. The kids are still young and can easily find paparazzi photos of them on their phones.”

Younes Bendjima, Kardashian’s ex-boyfriend, posted direct messages allegedly between him and Disick. The content of the messages have apparently fanned the flames of frustration between Disick and Kardashian.

“Yo is this chick ok!?????” Disick allegedly messaged Bendjima alongside a photo of Kardashian and Barker making out during their European vacation. “Brooo like what is this. In the middle of Italy.”

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“Don’t matter to me as long as she’s happy,” Bendjima replied. “PS: I ain’t your bro.”

Disick allegedly worries that Barker and Kardashian’s relationship will strain Disick’s relationship with his children.

“He’s worried that she’s going to try to put a wedge between him and the kids,” the insider continued. “Younes outing him on social just made everything worse.”