Entertainment TV Source: Scott Disick Was 'Overwhelmed' by Being a Father The reality star has three children with ex Kourtney Kardashian By Aili Nahas Aili Nahas Aili Nahas is the West Coast Deputy News Editor at PEOPLE. She is also the TV deputy in Los Angeles as well as the Weddings Editor. Aili has spent nearly two decades in the entertainment industry and 12 years at PEOPLE. People Editorial Guidelines Published on July 8, 2015 01:00 PM Share Tweet Pin Email Photo: Seth Browarnik/Startraks After years of Scott’s troubled behavior, Kourtney put her children first and decided that enough is enough. Subscribe now to get the exclusive inside scoop on how Scott ‘threw it all away’ and why Kourtney finally ended it, only in PEOPLE! Fatherhood didn’t come naturally to Scott Disick. A source close to the Keeping up with the Kardashians star, who split from Kourtney Kardashian over the July 4th weekend, says that Disick wasn’t prepared to shoulder the responsibility of three children. “He loves his kids,” says the source. “But he was never ready to be a stay-at-home dad.” The father of Mason, 5, Penelope, 3, and Reign, 6 months – who admitted on the show that he was “freaking out” when Kardashian told him she was pregnant with their third child – has always allowed Kardashian, 36, to take on the heavy lifting with the children. “Scott rebels against the crazy responsibility of having three kids,” says the source. “He acts out, he drinks too much and he embarrasses Kourtney.” Penelope celebrated her third birthday on Wednesday. And after an especially tumultuous year for Disick, 32, that included two stints in rehab and a hospital stay for alcohol poisoning, sources say Kardashian couldn’t tolerate the out-of-control behavior any longer. Says a source close to Kardashian: “It was becoming a poor environment for the kids to be raised in, and she refused to let that be the case. They are her first priority. – With reporting by MELODY CHIU RELATED VIDEO: Kourtney Kardashian and Scott Disick Have Ended Their Nine-Year Relationship For more on Kourtney and Scott’s split, pick up this week’s issue of PEOPLE, on newsstands Friday