Kim Kardashian Says Tristan Thompson Will 'Never Change' After Cheating News Breaks

The Kardashians are not a family a cheating boyfriend would want to mess with. Sunday's episode of Keeping Up With the Kardashians documented Khloe Kardashian's third trimester of her pregnancy when the news hit of Tristan Thomspon's cheating scandal.

With Kardashian, 34, in Cleveland with Thompson, 27, the rest of the family reacted in real time to the photos and videos surfacing of Thompson with other women — just two days before Kardashian went into labor.

Kim Kardashian, Kourtney Kardashian, Kendall Jenner and Kylie Jenner all furiously texted one another about the scandal.

"There's video of Tristan making out with a girl last night," said Kim, 38. "Khloé's going to die. She's literally going to go into labor over this."

"I can't even imagine being in Khloé's shoes, just how reckless it all seems — this is really shocking and obviously heartbreaking," Kourtney, 39, added. "The whole thing makes me disgusted."

"She kicked him out. He left the house," Kendall, 23, revealed. "We're trying to get her to come home."

Eventually, someone had to break the news to Kardashian. It ended up being Kylie, who had just had a baby of her own and whom had grown close to Kardashian during their simultaneous pregnancies.

"No one had the courage to tell Khloé because we knew she was days away from giving birth," Kylie said. "We didn't want to stress her out, but we knew that it was the right thing to do. So I'm the one that told Khloé. I didn't want to hurt her feelings, but I felt like she's hold hear from one of us versus on the internet."

Kardashian called Kim crying, saying she wanted to return to Los Angeles but wasn't sure if she could travel so late in her pregnancy.

"You just have to worry about yourself right now and be calm," Kim said.

"I can't be calm," Kardashian said. "Not right now."

Kim said she felt "helpless" over the situation as Kardashian tried to make a decision.

"She's confused, she doesn't know what to do and we don't really know what to do, but we want to be there for her," Kim said. "Honestly, I'm in shock. We love Tristan. This is honestly nothing that we suspected. We thought she finally found her Prince Charming, [her] happy ending. And then f—. It's just, why her? It just really, really sucks."

Apparently, the cheating rumors being reported were not the only ones reaching Kim's ears.

"Honestly, so many more stories are coming out," she said. "So many friends are calling me with so many more things. I told her, 'What are you going to get out of him? Think about it. You're going to be worried and nervous and have an insecure life, because if he's not faithful now, he'll never change.'"

"When one thing comes out you're kind of like, well, okay, maybe the video's old or maybe it's a misunderstanding. Because a picture doesn't always tell the full story," Kim added. "But then two more stories come out. This is just crazy. Now you know it's true."

But before Kardashian could fully process the rumors, she went into labor and asked her sisters to remain civil with Thompson, whom Kardashian still wanted to be in the delivery room.

"It's like, everyone wants me to make a decision right this second and I just want to go and give birth and focus on that and try to enjoy this and try to enjoy it with him, as crazy as that sounds," Kardashian said. "I want to enjoy this with him. I don't want any negativity in the delivery room. I don't want anybody to talk about it, make me feel uncomfortable or make him feel uncomfortable. Let's just act normal. Give me a minute."

Kim said she's be civil with the NBA player, but made it clear it wasn't her first choice. "I'm going to look at him and just be like..." she said, miming cutting her throat.

Kourtney agreed that it would be tough not to say anything to Thompson. "I know how important it is for Khloé to have Tristan there, and I actually really respect that," Kourtney said. "But it's definitely going to be awkward. It's going to be hard to even look at him or even be in the same room with him. It's like, you are f—ing with all of us when you disrespect one of us."

Ultimately, Kardashian decided to stay with Thompson. The couple spent the summer in Los Angeles with their daughter, True, rebuilding their relationship. But the two appear to have hit another rough patch recently.

A source told PEOPLE that Kardashian has been having a "really tough" time and "still has a lot of hurt and anger" amid her decision to do what's best for True.

"Khloé wants so badly for True to have a happy family," the source said. "She wants to do what's best for her daughter, and to her that means being with Tristan."

Keeping Up With the Kardashians airs Sundays at 9 p.m. ET on E!