In my experience, you cannot move seemlessly from a relationship into friendship unless you both feel equally unattracted to each other.
The fact that this guy still loves you is always going to put a crimp in any friendship you may try to have together - for you because you can't relax and be yourself, including running your latest boyfriend past him for the OK, and for him because he is contanstly reminded of a relationship he can't have, while being simultaniously unable to get over loosing you, and move on.
You need to split from him competely - no contac at all.
Sounds harsh, but in the long run it's best for both of you.
You don't need the flattery of unrequited love, he doesn't need the pain of always wanting you back, and never accepting that it's not going to happen.