Rob Kardashian Blames Cheating Ex-Girlfriend for His Insecurities on 'Rob & Chyna'

It's not a secret that Rob Kardashian has some intense jealousy issues, but in the second episode of Rob & Chyna on Sunday night, the reality star attempted to explain the root of his problems.

After butting head with his fiancée, Blac Chyna, in the show's premiere, Rob wasn't quite ready to forget the fight.

WATCH: Rob Kardashian Admits He's Scared Blac Chyna Will 'Stop Being Attracted' to Him Because of His Weight

"I had a really bad past relationship where the girl was cheating and having sex with so many different people," Rob, who famously dated both Rita Ora and Adrienne Bailon, noted.

Eventually, Rob did apologize, though he opted not to move back in with Chyna, saying the space was good for him. And though he promised to join Chyna in Cannes for an event, Rob ended up bailing due to problems with his weight.

"I'm not comfortable in my skin, I'm not comfortable with this weight, I feel like I'm not happy with anything I do," he said.

His lady love was not impressed, calling him "f**king whack," but she later came around and apologized.

WATCH: Rob Kardashian Apologizes to Blac Chyna, But Doesn't Want to Move Back in: Watch the 'Rob & Chyna' Clip!

"I can understand why you feel a little bit insecure about your body and stuff," Chyna said. "Maybe I need to be more supportive of that and not be so hard on you, too. I'm just sorry for being rude."

For more from the emotional second episode, watch the clip below!