Just Got Out of an abusive relationship, but why do i feel like I want him back?

I just got out of an abusive relationship. And already I'm thinking about him. I was with the guy for two years. He did nothing but treat me like s***, then go back to being nice, then go back to treating me like s***. He choked me before, just because i tapped pushed him after he spit on me. Yesterday he ended the relationship with me because he said that i betrayed him, because in some text messages I wrote to his bestfriend's girlfriend that he treated me like s*** during the time we had an agurement. And hes not being a good boyfriend to me. So I guess she went and showed it to him. And he was like you betrayed my trust, I thought i could trust you. I kept saying how do yo betray someones trust if you didn't lie. Thats how i felt at the time. So anyways he was like its over i dont' love you anymore all this stuff. Saying I dont' love him, and i'm not even sorry. I didn't say sorry for something that i thought wasn't betrayal. So I gave back his promise ring and called him a loser and he key's my car. So my father went to his house and talked to him and I guess he was trying to act like the whole time he loved me and stuff. Plus he said he was getting a restraining order on me??? Are you kidding. So he said to stay away from me and stuff so I think i'm gonna be fine now. But I'm just going thru this faze of " I don't understand why" and blaming myself. I have no friends to talk to or anything. Can someone just please tell me why this guy acted this way to end it??? And why the hell am i still thinking about him like its my fault??