In a sneak peek at Sunday's episode, Khloe attempts to smooth things over between them, but just gets fed up in the process.
"I feel like you think you can go out and do whatever you want and purposely try to hurt me and still get invited to everything," Kourtney tells her ex. "That's not a way to show your love. When someone's trying to f-ck with me, I'm not into having them at my sister's party."
"When you intentionally are trying to hurt me, like tit for tat, that doesn't make me want to be like, 'Let's invite Scott to the party," she added.
"I am on the longest ferris wheel of all time, we gotta get off the ride at some point and get on a new one," says a frustrated Khloe. "It's the same old story over and over and over again."
Scott then admits he doesn't "have the best support time" and adds he's like to "try to f-cking be a better person," but Kourtney says she's done trying to help. "You already know the things you should be doing in life, you don't need me to tell you them," she explains, "we're not gonna sit here and go over it again for the 100th time in ten years or more."
Though Khloe commends her sister for standing up to Disick, she's not entirely optimistic it'll stick, especially after Scott asks when they're "gonna get married."
"You think that when I turn 40 I'll be like, 'Hey, I've been looking for this drunk guy and he has a bunch of dirty sh-t stain underwear?" Kourt jokes, before the two head out together to run some errands.
"You guys are so f-cking dysfunctional and I don't know if this is something you do as foreplay, but this is nuts," Khloe exclaims. "You two are so f-cking nuts, seriously. The fact that you waste my time when you go get mani-pedis together!"
The two recently spoke about the status of their relationship during the 10-year anniversary special, where she shot down any shot of a reconciliation.
"The debauchery that's gone on has definitely closed the door several billion times," she said at the time. "He does [get better] for a time period, he can't be consistent."
She also ends the clip above by ensuring Khloe the two "don't hook up."