Do you feel that way because you want to be his friend, or because you feel like it'll make you a bad person if you aren't? Either way, the most important thing here is your health and happiness. It sounds as though you've already made great progress in no longer thinking of being with him - this is just the next step, and like those other feelings it will pass in time. Just remember that you don't owe him anything, especially if he hurt you - not your time and not your friendship. It may be difficult, but the best thing you can do is to try not to think of him.
