Tough past... how should I share?

I had a very troubled past. Sexual and physical abuse dominated my childhood until I turned 16 and ran away from it all. It’s been hard, but I’m in a good place now. I’m 21 and have a steady job, a car, an apartment, and even going to college to study psychology. I have no idea how, but life has really turned around. I have no connections to my past family (no desire to) and have finally opened up to dating.

Sad part is, I’ve had bad reactions to my past. One guy even broke up with me telling me that he didn’t want to be with someone “who’s been used”. It’s horrible I know, and that really broke my heart because although I know my past doesn’t define me, it is the reason why I turned out so head strong and opinionated.

But I don’t want to scare off this guy I started seeing. He’s really sweet, laidback and soft spoken, and I can’t deny that this isn’t easy to take in. It was scary childhood. I can’t sugarcoat that. But i shouldn’t have to pretend it never happened. There’s nightmares (ptsd), mistrust (Im uneasy around older men), paranoia (that my father will find me). Not to mention how I deal with sex... it takes forever for me to build up that trust. How can I bring up this topic? I know this is hard, and i just need some tips girls, anything will help.