Rob Kardashian Cheated on Adrienne Bailon:

So, it turns out Rob Kardashian cheated on Adrienne Bailon. For those of us who wondered exactly why the Kardashian sibling broke up with the former Cheetah Girl, Rob admitted on Sunday night's episode of Keeping Up With the Kardashians that his cheating led to their breakup.

But who did Rob cheat on Adrienne with? A remorseful Rob didn't reveal that bit of information.

We feel bad that Rob is dealing with a broken a heart, but the fact still remains that he cheated. Now Adrienne, who he dated for two years, has moved on with her life - as Rob found out when her new boyfriend sent him a text message at the end of the episode. Sorry, Rob!

Back when Rob and Adrienne Bailon were a couple, Adrienne made frequent appearances on Keeping Up With the Kardashians.

In one episode, the Kardashian family and Adrienne's family went camping together. Adrienne was also a guest at Khloe Kardashian's recent wedding to Lamar Odom.