The break up took place aparently after the 37-year-old "Keeping Up With the Kardashians" star saw some pictures of him cosying up to his ex Chloe Bartoli in Monaco.
The couple, who started dating in 2006 and briefly split in 2010 before rekindling their romance later that year, have ended their relationship, reported The Daily Mirror.
"Kourtney has always taken Scott back and been by his side, but now with three kids it has gotten old. Kourtney has to do what's best for the kids," a source said.
"Scott has been running around saying he's single. Kourtney dumped him after she saw the pics and he hasn't been home after a month-long party binge," the source said.
According to an insider, Disick has been spending time with friends who "are not a good influence" on him.