Kim Kardashian is getting real about how Blac Chyna felt when her ex, Tyga, started dating Kylie Jenner. In a sneak peek of Sunday’s “Keeping Up With the Kardashians,” Kim reveals that her former BFF was really devastated over the pair’s romance.

While talking to sisters Khloé and Kourtney Kardashian, Kim says that she called Rob Kardashian to talk, and he tried to get her to patch things up with Chyna. Kim explains that she wasn’t ready to face Chyna yet, but Rob put them on the phone together anyway.

“I just told him that I’ll talk to her when I’m ready. And so he put me on speaker and then he was like, ‘Oh Kim, Chyna’s in the room, I just wanted to tell you so you didn’t think I was alone,’” she tells her sisters. “And then she goes, ‘Hi.’ … I froze.”

Kim says because she didn’t know what to say to Chyna she just hung up the phone on her. In a confessional, the mother-of-two explains that she felt bad for the model but had to stick by her family’s side. “I understand that Kylie dating Tyga completely broke Chyna’s heart,” she says. “I feel for her in that situation. Was it uncomfortable for me when Kylie and Tyga started to date? Absolutely, because Chyna was my friend, but I had no choice but to take my sister’s side.”

As previously reported, Kylie and Tyga split earlier this month after dating for two years. Chyna has been dating Rob since January and announced recently that they’re engaged and expecting their first child together.

It’s been reported that Rob and Chyna’s relationship actually caused a few problems for Tyga and Kylie and may have contributed to their breakup. “The drama really started to get to Kylie,” a source told People magazine. “She couldn’t get it off her mind. She almost felt like she was in an incestuous relationship. She figured it’d be best to just drop it and move on with her life so she wouldn’t have to worry about all the emotional baggage that came along with that situation anymore.”