Kourtney Kardashian breaks up with long-time beau Scott Disick.

After pictures of Disick and another women in Monte Carlo surfaced over the weekend, E! News exclusively reports the couple have called it quits.

The couple who has been dating since 2006 have three kids together, Mason, 5, Penelope, who turns 3 on Wednesday and 6-month-old Reign.

"Kourtney has always taken Scott back and been by his side, but now with three kids it has gotten old," a source said. "Kourtney has to do what's best for the kids."

During the various seasons of Keeping Up With the Kardashians and it's spin-off series, Disick was seen battling substance abuse problems, which effected their relationship.

Disick checked himself into rehab earlier this year and Kardashian told E!, "He's doing well, and you know, focusing on himself and working on himself. He's made a lot of progress, so I'm proud of him."

But now his partying antics have cost him his relationship with the 36-year-old. "Scott has been running around saying he's single," The source said. "Kourtney dumped him after she saw the pics and he hasn't been home after a month-long party binge."

Koardashian nor Disick have commented on the break up.