Have you told your parents?

Maybe try coming forward like this: Sit down someone you trust explicitly, and explain that what you are about to tell them is real, and very serious, and that you need help. Ask them not to interupt you till you are done. Then tell them that you don't like your ex, you don't want anything to do with him, but you are afraid that he will hurt you. Explain that this is justified because he has hurt you before. Write it out in advance if you need to.

This is not your fault. You are not being selfish. He has no right to touch you, in any manner, even it's just hugging. Don't ever let yourself be alone with him. If he's nearby, then stick with a friend until he's gone. Take steps to protect yourself.

Have you ever taken a self-defense class? If not, you should consider it. It will add confidence and give you a way to protect yourself if you do find yourself alone with him, so you won't have to be afraid anymore.

Don't stop reaching out or looking for help.