All the drama caused by the messy split between reality TV stars Kourtney Kardashian and Scott Disick is proving to carry a heavy price on their children.

Radar Online reports their 5-year-old son Mason is already in therapy, as he struggles to understand and accept his new reality.

"Mason tells her when Daddy acts 'mad, sad or weird,'" a source said of Kardashian. "Kourtney knows it's important that her kids see their father, but it breaks her heart to think they'll remember Scott like this."

The 32-year-old Disick recently raised eyebrows when he was rumored to be overheard snapping at his kids while they were at a L.A. bookstore. Witnesses described him as "antsy," as he anxiously implored his kids to quickly make their purchase selections.

All the back and forth is rumored to have left Kardashian a nervous wreck whenever the couple's young children are left in their father's care.

"She's always calling to check on them," a source told InTouch, adding that Kardashian still doesn't let Disick be alone with their newborn.

The tension has resulted in Kardashian laying down some strict rules for her ex. Disick is only allowed to spend time with the kids over the weekend and must have them back home no later than 8 p.m., with no possibility of sleepovers.

Since the couple's summer split, Disick has fallen deeper into his party-boy lifestyle, reportedly often appearing distracted when his kids are around.

"Scott barely pays attention to the kids when he has them," a source added. "He just gives them whatever they want to keep them occupied so they're not crying."

After nine years, Kardashian and Disick split in early July, after he spent the Independence Day holiday weekend in Monaco affectionately hanging out with ex- girlfriend Chloe Bartoli.