How do I get over a cheater?

You can't tell her to stop hanging around your friend. They're going to hang around no matter what. If they listen, that's something new. You can't just "get over" certain things. That stuff takes time. Just don't see her anymore, don't hang around the places she hangs around. Find new things. Play video games, read comics, surf, skate board, learn to play a mandolin, paint pictures, etc. Do something to get your mind off of her. Don't hang around the friends she hangs around. I don't think your friend was a bad friend, whoever did tell you was being honest. I just don't recommend you hang around that person if you have such a problem with your ex hanging around them. Sounds like nothing but trouble. You can't "own" friends and tell them who not to hang around/who to be friends with.