Kim Kardashian Says Tristan Thompson Will 'Never Change' as He Cheats on Khloé on 'KUWTK'

Sunday night’s episode of Keeping Up with the Kardashians took fans inside Tristan Thompson‘s cheating scandal — and revealed how Khloé Kardashian and her famous family reacted in real time.

When photos and videos surfaced of Thompson, 27, getting close to another woman just two days before Khloé, 34, welcomed their baby girl on April 12, the mom-to-be was nesting in Cleveland. As the news broke, cameras captured Kim, Kourtney, Kendall and Kylie all reacting separately back in Los Angeles, furiously texting one another about it.

“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,” added Kourtney, 39. “The whole thing makes me disgusted.”

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

It turns out that Kylie, 21, was the one to break the news to her sister.

“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 should hear from one of us versus on the internet.”

Finally, Khloé called Kim crying, admitting that she wanted to fly back 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,” Khloé said. “Not right now.”

Kim admitted to feeling “helpless” over the situation as Khloé tried to figure out what she wanted to do.

“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.”

And Kim had been hearing about even more rumors of Thompson’s infidelity.

“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 Khloé could decide the future of her relationship with Thompson, she went into labor. As her mom and sisters made arrangements to get to Cleveland as soon as possible, Khloé asked that they remain civil when coming face-to-face with Thompson, at least 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,” Khloé 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 agreed to remain cordial — but not without cracking a few jokes about how she would greet him.

“I’m going to look at him and just be like …,” she said, miming cutting her throat.

“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.”

RELATED VIDEO: Khloé Kardashian Claps Back After She’s Accused of ‘Embedding Materialism’ into True with Gifted Car

As PEOPLE previously reported, Khloé ultimately decided to stand by Thompson, and they spent the summer as a family, rebuilding their relationship in Los Angeles. In recent weeks, however, the couple hit another rough patch.

According to a source, the new mom has been having a “really tough” time and “still has a lot of hurt and anger.”

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

But Khloé’s mom and sisters “aren’t happy” about her move back to Cleveland and “think she deserves better,” the source said. “They definitely don’t trust him.”

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