I also don't understand what you're asking.
"for now I just want exclusivity, no promises of a relationship necessary yet. " How do these two things go together ?? There is exclusivity only in a bf/gf relationship.
Its understandable to be cautious but so much that you lose as to what constitutes a relationship.
I am sorry but if he is not ready to be in a relationship now and you wait ,he may suddenly find someone with whom he really wants to be and is ready.So to tell you 'not ready' could be interpreted as 'not ready for you'.If you want a relationship, tell him so.Playing around as friends is ultimately going to turn into friends with benefits and you dont want that,I presume.When you go around as friends,have sex but are not in a relationship ( as he is not ready )-- FWB.Its good to be friends but not zoned.
.....We both know that I have been waiting for him to be ready for us.".....