I didn't mean to seem harsh, just realistic. Surely you can imagine how hard it would be to hang out with/call someone with whom you want a more serious relationship. He doesn't want to be just your friend and it's torture for a person in that situation to have their nose rubbed in their frustration daily.
So if you don't feel the same attraction, it would be kindest to let him go rather than keep him around in limbo just to keep you company.
On the other hand, if you DO feel some attraction but truly wish to take it slow on an intimacy level....and if you've made that absolutely clear to him....his disrespect of your feelings is troubling. I might suspect that it is all he wanted. I also might suspect that the cold shoulder now is some kind of emotional blackmail to make you more pliant?