Kourtney Kardashian is worried Scott Disick will 'go back to partying' after Sofia Richie split

Kardashian, 39, is afraid Disick, 35, will start partying again in the wake of his split from girlfriend Sofia Richie, a source tells PEOPLE.

“Her concern is that Scott will go back to partying every day and be MIA,” the source says. 

The exes dates on and off for nine years and share three children: sons Mason, 8, Reign, 3, and daughter Penelope, 5.

PEOPLE confirmed the couple had split Saturday after Disick was spotted looking flirty with a mystery woman at Kanye West‘s Ye listening party in Jackson Hole, Wyoming, on Thursday night. Disick reportedly told guests that he was single, according to TMZ.

Another source close to the former couple tells PEOPLE that Sofia ended the relationship after confronting Disick about cheating on her.

And while the source says Kardashian always thought Richie was “too young” for Disick, the 19-year-old helped keep him on a healthy path.

“Sofia was a good influence on Scott,” the source says. “Since she has been around, he has been drinking less and acting more like an adult.”

With his partying ways in the past, the source says Disick was also a more attentive father to his kids — something Kardashian hopes doesn’t change because of the breakup: “The kids are all very happy that Scott is around and Kourtney would hate for that to change.”

Richie has moved out of Disick’s home to stay with her father, music icon Lionel Richie.

As for how Sofia is adjusting to the breakup, “She seems to be doing okay,” an insider told PEOPLE over the weekend. “She is surrounding herself with girlfriends and keeping busy.”

This article originally appeared on PEOPLE.