I agree with James. It is possible to be friends in some circumstances (my best friend is my ex) but it does not sound like your present situation is one of them.
It sounds like you're not over him and are maintaining the friendship in the hope that a) you will get back together or b) you will get some kind of closure on why he treated you so badly.
I suspect neither are forthcoming.
Be honest with him and say you still struggle with feelings for him and realise it's not healthy for you. Tell him you need to take a few months apart to get over it. (Three is a good start, six would be better.) Then actually take them. Don't contact him, make the effort to meet new men, spend time with your girlfriends and talk it out. Part of the reason you're not over him is because you've tried to maintain a friendship you weren't ready for on false grounds.
If he's going to realise he misses you, he needs to actually have time to miss you. If it turns out you can be friends, a six-month break is nothing in the grand scheme. And if neither is possible, you need the space to gain perspective and move on.
Frankly, if someone treated me the way he did you, they wouldn't be getting a second chance at friendship, let alone a relationship, but your mileage may vary.