"It's called giving someone a heads up and having a respectful conversation," she says in a sneak peek at Sunday's episode of KUWTK

This season of Keeping Up with the Kardashians has been all about Kourtney Kardashian clashing with her sisters Kim and Khloé — but it looks like Scott Disick just got thrown into the rotation.

In a sneak peek at Sunday’s episode, things get tense between the exes as they sit down to discuss where they stand on co-parenting their three kids. According to E! News, the conversation comes after Disick, 35, decided to introduce his girlfriend Sofia Richie, 20, to the children.

After Disick calls Kardashian, 39, “annoying,” she tells him to “be appreciative of what you have.”

“And you don’t think I am extremely appreciative?” he says.

“Not when you just do whatever you want,” she responds.

“What’s whatever I want? Live my life the exact same way you’re living it?” he fires back.

“It’s called giving someone a heads up and having a respectful conversation — giving someone the respect,” she says.

Disick points out sometimes things “don’t always go as planned,” but his ex feels like that’s just “an excuse.”

“I make sacrifices all the time and you’re not following through with the things you say you’re going to do,” she says. “Then you just go and do whatever you want, and I’m not okay with it.”

“Do you think you’re difficult, or no? Do you think you’re overly controlling?” he asks. “Do you think there’s any chance you could ever be in denial about anything?”

RELATED VIDEO: Kourtney Kardashian Says She’s ‘Ashamed’ of Her ‘Disgusting’ Family: ‘It’s Just Gross’

Kardashian explains that she expects “a lot” for her kids and just wants the best for them, admitting she’s a “perfectionist.”

“I think you expect a lot from a lot of people,” Disick says with a sigh. “But not always can your expectations always be met, even though people are trying their hardest to please you.”

DuJour's Jason Binn And WellNEST Celebrate Miami Beach's Art Basel Kick-Off
Scott Disick and Sofia Richie
| Credit: Andrew Toth/Getty

Disick and Richie have been dating since last fall. Though the relationship raised eyebrows at first, sources later told PEOPLE that as long as it helps keep the father of three on track, they have Kardashian’s blessing.

“Sofia is helping Scott be a better, healthier person,” said one source. “Kourtney feels confident that Scott and Sofia take good care of the kids. Scott is a great dad when he has his life together.”

“It helps that Kourtney now trusts Sofia,” added a second source. “The kids are allowed to spend time with her. Sofia likes having them and helps Scott. So far, the kids are giving Kourtney good reports about Sofia.”

“Sofia has shown over and over again that she is willing to stay with Scott even when things are not great — but Scott is doing well lately,” added the insider.

Keeping Up with the Kardashians airs Sundays (9 p.m. ET) on E!