Kourtney Kardashian is putting her kids first. The reality star has called it quits with her longtime boyfriend Scott Disick for the sake of their children.

"Kourtney is willing to sacrifice her relationship with Scott in order to keep [her kids] safe," a source told People. "Her children are her first priority. She needs to protect herself and her family, so she knows this is the right decision."

Kardashian had enough of Disick's drinking and party antics. The final straw came when photos surfaced of him and ex-girlfriend Chloe Bartoli partying in Monte Carlo over the weekend. The pics also showed the two sharing a lounge chair and Disick giving her a back rub.

"He acts out, he rebels, he drinks too much and he embarrasses her," the source said. "He just rebels against the crazy responsibility of having three kids and makes Kourtney do it all."

Lord Disick reportedly hasn't returned to the family's home in Calabasas, Calif. in over a month and has told people that he's "newly single." He and Kardashian started dating in 2006 and have three children together - Mason, 5, Penelope, 2, and 6-month-old Reign.

"When he's sober he's actually a great dad," an insider told Us Weekly.

The oldest Kardashian sister has always welcomed Disick back into her life after he goes on his party binges, but only time will tell if she forgives him again.

"This was an escape for him, a way out. Kourtney is flipping out and going crazy and says she's done with him but they've been through this before," the insider said. "He just hasn't publicly embarrassed her like this and to this level. She says it's over, but I know they will end up getting back together for the kids and the show."

"Keeping Up with the Kardashians" will continue its 10 season later this year.