How do I get over This?

So in my past relationships I’ve been hella scared of loosing my partner and being alone in the long run. So I would constantly jump from relationship to relationship.

I believe it started when I was physically and verbally abused by the person of my dreams. They were so wonderful, but they got mad easily. I loved them. They would tell me how worthless I was and how no one would actually love me. They would tell me that If I left them No one would ever want to date me again. I remember on several occasions they would degrade me and hurt me. Recalling all the events in that relationship doesn’t make me feel happy.

Anyways, there is this guy I like. I want to be romantically involved with him. He’s so nice and he’s cute too. Just every time I think about even telling him I get all depressed. I just remember how no one could ever love me. I then think that if i did get in a relationship with him, he would treat me like my ex.

I’m afraid of being alone, yet afraid of being in a relationship. How do I get over this?