Kim was initially tipped off by her friend Larsa Pippen, who said a reporter was writing a story about Thompson and Woods.
"[The reporter] was about to write a story that Jordyn and Tristan were at his home late night or until seven in the morning. They said they were making out. I immediately didn't believe it. I was like, this can't be true," Kim says in a confessional shot.
The promo shows Khloe, Kim, Kourtney and Kylie's group phone conversation, during which Khloe says Jordyn was not being forthcoming.
"I talked to Jordyn. It's really weird. She's not giving me all the information," Khloe tells her sisters. "She was like, 'He was trying to kiss me,' and was like, 'I can't remember if we did or didn't.'"
Woods, who was Jenner's best friend at the time of the scandal, said in an interview with Red Table Talk in March that Thompson kissed her after a night of partying in February.
"On the way out, he did kiss me," Woods said. "No passion, no nothing ... It was like a kiss on the lips. No tongue kiss, no nothing."
"I didn't know how to feel," she added. "I walked out immediately after ... I was in shock. I was more so like, 'Did this really [happen]?' I was like, 'Hmm, let's pretend that didn't happen.'"
Khloe and Thompson, who are parents to 14-month-old daughter True, split in February following the scandal. The pair were first linked in September 2016, and Khloe denied last week she knowingly cheated with Thompson during his relationship with Jordan Craig.