<human>: Give me the gist of the text in a nutshell

I never fell so hard for a guy before. I had a crush on him for years before asking him out. 

It was going great and we had a really really good time, we could have sex for hours, cuddle, have the best conversations and repeat without ever getting tired of each other. It's the happiest I have ever been in my sad little life. 

After the first time we picked a fight (I don't remember what it was about something silly) I knew he could be violent. I brushed it off, told myself he was just being overly dramatic and demonstrative when he was angry... But of course it only got worse with time. Last time we picked a fight I got really scared for my safety. I told him to leave and not come back. 
 
I'm heartbroken. 
I know I can't be with someone like him. 
I can't imagine not being with him anymore. 
I feel sick, this never happened to me before, I never got so depressed about having to get someone out of my life. 
The only other relationship I had before him was over before the break up so I wasn't sad when it ended... But now I'm demolished. I'm sure if he apologized I'd run back to him. 

How the hell do I pick myself up and move on? How can someone be so loving, interesting and make you feel safe one minute and turn into a psychopath the next?
<bot>: Was in love for the first time, with an amazing guy who turned out to be violent and I can't move on, I feel sick, I need help.