How do I get my ex to stop touching me?

It s nothing inappropriate, but he knows that I hate being touched. He pulls my hair, slings his arm around my shoulders, touches my face (which I especially hate) and he pokes me. He loves physical affection, and that is something I absolutely despise which is why our relationship fell apart. I m constantly telling him to stop and reminding him that I don t want to be touched. He stopped for a while after my best friend yelled at him and threatened to slap him the next time it happened. Then he started messing with me again. I don t have many friends so I want him to stay around, but he won t respect my boundaries.