Kourtney Kardashian and Scott Disick argue after he introduces kids to Sofia Richie

Co-parenting isn’t easy – especially when other relationships are involved! In a new sneak peek of the Sunday, September 9, episode of Keeping Up With the Kardashians., Kourtney Kardashian. gets irritated with ex Scott Disick. after he introduces their kids to his girlfriend Sofia Richie.

“I’m saying be appreciative of what you have,” the reality star, 39, tells Scott, before adding that he does “whatever you want.”

“It’s called giving someone a heads up and having a respectful conversation, giving someone the respect,” Kardashian tells her ex, 35, referring to him introducing his girlfriend to their three children Mason, 8, Penelope, 6, and Reign, 3, without discussing it with her first.

“Sometimes you want to do certain things or you map out certain things but they don’t always go as planned,” he replies. However, she sees that as an “excuse,” saying that she continually makes sacrifices while he does not. He seemingly gets even more frustrated and calls her “difficult” and “overly controlling,” but for her, she believes she’s just doing what’s best for the kids.

“I think you expect a lot from a lot of people,” Disick tells his ex. “Not always can your expectations always be met, even though people are trying their hardest to please you.”

While it may be awkward for Disick to be dating Richie, 19, Kourtney has no problems with the model, a source told Us Weekly exclusively last month. “There’s no beef between her and the family. They actually think she’s great for Scott,” the insider noted.