I can't let go of my ex even though he's abusive...?

I don't know whats wrong with me but I am putting myself through hell and I don't know why I keep doing it to myself. I was with a guy for a year and he has said and did the most horrible things to me and I keep going back to him. I lost my virginity to him and I'm thinking thats why but he calls me a whore,hick,*****,kill myself,wishes death on my family,says he'd spit in my face,loser,he hates me im a retard and sends me picks of him ******* girls. I think something is wrong w me but I still love him and I'm scared cause he has all these girls who wanna be his girlfriend and some of them are my ex friends and I think im scared to see him with someone else. And since we have broken up i kissed a couple guys on my vaca and he always has a way of making me think he doesnt do things and i feel guility to tell him and when i do then he says hes gunna go **** my friends Help me please.