How long has it been since you split? I was with someone abusive for a few years and I still loved them when I left them, even thoughts were abusive, it took me a long time to stop dreaming about them, I'm just told myself I was free and I now had a chance to be happy every day, and eventually they went away. If you have bad dreams focus on the good things when you're awake, don't try not to think of him, just fill your mind with all the good stuff in your life, in the present. It can take a while. Sometimesnyou have to find closure for yourself, make up a reason that you can believe so you know it wasnt your fault, you didn't deserve the abuse and it was something wrong with him. If you dream of him still he is probably still on your mind in the day, be kind to yourself and do things that make you happy, you'll be so focused on the good times you're having and the good book or film you're watching that you'll start to forget about him. Maybe do the things you werent allowed to when you were with him but always wanted to do. It's all about self love. I know it's hard and can seem impossible sometimes, but keep telling yourself you're amazing and eventually you'll believe it, and when you love yourself fully you can be happy, and you won't think of him any more, or if you do sometimes it won't bother you. Give it time and love yourself