"I make sacrifices all the time," Kourtney says in the clip. "And you're not following through with the things that you say you're gonna do."
In a preview for this Sunday's "Keeping Up with the Kardashians," Scott and Kourtney participate in a heated stand-off after Scott introduced his girlfriend Sofia Richie to their kids. In result, Kourtney goes off on her former flame for not showing her "respect" and doing "whatever" he wants all the time. Scott ultimately snaps back at his ex for her "controlling," "difficult" and "annoying" personality.
In the clip, Scott tells Kourtney that she was "pretty annoying" during the meeting. The eldest Kardashian retorts that he needs to be "appreciative" and respectful because she lets him still be a part of the Kar-Jenner clan.
"It's called giving someone a heads up and having a respectful conversation, giving someone the respect," the oldest Kardashian explains.
Scott replies that sometimes things don't "go as planned," but Kourtney says this is all an "excuse" for Scott to do "whatever" he wants.
"I make sacrifices all the time," the eldest Kardashian explains. "And you're not following through with the things that you say you're gonna do. Then you just go and do whatever you want and I'm not okay with it."
Scott then asks Kourtney if she believes that she's "overly controlling" or "difficult."
The mom of three says that she's not either of those things, but had to be that way when she and Scott dated. Scott questions whether Kourtney feels that she could "ever been in denial about anything."
"No," Kourtney replies while laughing.
"Okay, I rest my case," Scott responds and stands up.
Kourtney defends her response and says that she just wants what's "best" for her children.
"I expect a lot for my kids," she points out. "I want the best for them."
"I think you expect a lot from a lot of people," Scott snaps back. "Not always can your expectations always be met, even though people are trying their hardest to please you."
Kourtney replies that she "understands" that she's a "perfectionist," but says she really tries to not be "controlling."
"I will bet you one million dollars there's not a human being that you know that won't go with exactly what I just said," Scott concludes.
"Keeping Up with the Kardashians" airs Sunday night at 9 pm ET on E!