If it weren't for her bruises and his bruises, I wouldn't believe her. Her behavior was erratic and her accusation of Elliot was really a nail in her coffin. HOWEVER, I don't buy HIS story of:

"I'm not into rough sex, but she wanted it rough and if I didn't do it rough, she would bite or scratch me, so I gave her what she wanted."

Sorry, don't buy it. If you don't want to engage in rough sex, you don't choke the hell out of somebody. If you don't want to have rough sex and somebody bites you that damn hard, you stop.