Entertainment TV Kourtney Kardashian Denies Hooking Up with Ex Scott Disick in 'KUWTK' Reunion Sneak Peek "People cannot believe that, but we have not," she says By Aurelie Corinthios Published on June 18, 2021 12:00 PM Share Tweet Pin Email Scott Disick is in the building. Kourtney Kardashian's ex will join the family for part two of the Keeping Up with the Kardashians reunion, airing Sunday on E! — and no question is off-limits. In a sneak peek, host Andy Cohen gets right into it, asking Disick, 38, if he thinks his relationship with Kourtney, 42, would have lasted if he had maintained his sobriety. Disick and Kourtney both say yes, and Kourtney adds that Disick's substance abuse was the biggest "dealbreaker" in their relationship. "I mean, the infidelity, I only knew about it at the end," she says. "So I think the substance abuse was the dealbreaker." Disick himself admits his hard-partying ways led him down the wrong path at times. "I don't want to make any excuses for my behavior," he says. "I definitely wouldn't have done these things sober. But it was all wrong, and I just thought it was normal, to be honest." Scott Disick Learns He Has Low Testosterone, Says His Body Took a 'Beating' from Drinking Keeping Up With The Kardashians/Youtube Disick has struggled with alcohol abuse in the past and in 2015 checked himself into rehab following his split from Kourtney after nine years together. The exes, who share three kids, have both since moved on — Kourtney is dating Travis Barker, 45, and Disick is dating Amelia Hamlin, 20 — though their relationship has remained a focal point of the show. In the sneak peek, Cohen asks a burning question: Have the two slept together in the last five years? "People cannot believe that, but we have not," Kourtney says. "For real." "How annoying," Disick jokes. Kim Kardashian Avoids Specifics About Kanye West Split During KUWTK Reunion, Denies Dating Van Jones These days, "we're great friends and co-parents," Kourtney says, to which Disick adds, "I mean, we're family. I think we always will be." As for how Disick feels when Kourtney is linked to other men? "I just want to kill 'em," he jokingly mutters under his breath. Then, seemingly referencing Kourtney's ex, model Younes Bendjima, he adds, "The last guy — let's all be honest here." "Nobody was happy with the last one," Khloé Kardashian agrees. Part two of the KUWTK reunion airs Sunday at 9 p.m. ET on E!