What should I do, who was wrong?

Me and my friend was walking around the track when my ex boyfriend (2day ex) came up behind me and grabbed my neck with one hand when I asked him to stop he began pulling on the back of the neck of my T-shirt. I asked him to stop and explained to him that he was stretching my shirt and pulling against the front of my neck. I basically begged him to stop he wouldn't stop. I even stopped walking and turned to him and asked him to stop. He continued so I slapped him in the face. He retaliated, by slapping me in the face and knocking my gles off. I wanted to beat the crap out of him. Later in the night he "called to apologize" but he kept telling me that I provoked him. Then he called a second time and begged for my forgiveness. He ask me if I still love him. I care about him but I just don't know what to do.