Chris Brown
Chris Brown is one of pop and R&B's shining stars for a time, that is until he started dating Rihanna. At a pre-Grammy party in 2009, the two got in a heated fight, and Brown actually physically attacked Rihanna. She left with a split lip, lesions on her forehead, and bruises on her cheeks. Brown has never been able to recover from what he did, and his reputation is rightfully tarnished.