"She cheated on me with nearly 20 dudes while we were together, I wonder how many she will sleep with now that we are apart?" he posted (although he's since deleted that particular tweet.)
Late Monday afternoon, Kardashian was still stewing.
"When a woman cheats on you with one man, I can live with that. People make mistakes, trust me. I have forgiven numerous times," Kardashian wrote. "But when a woman disrespects herself by messing with more than 20 men all while being in a relationship with a faithful man . . . "
Mused the E! standout, "I just don't get how a woman can do that to her body. And your career hasn't even launched yet. I don't put up with sloppiness. LOYALTY. This is a lesson to all the young women out there to not have unprotected sex with multiple men, especially while in a relationship."
Although he declined to ID the woman who had done him wrong, the Twitter-sphere was quickly abuzz with speculation that Kourtney, Kim and Khloe's younger brother was attacking British pop star Rita Ora.
Us Weekly confirmed the pair were an item back in December 2011.
This article originally appeared on Usmagazine.com: Rob Kardashian Accuses Rita Ora of Cheating?