I think when its got to that stage (boyfriend/girlfriend) its not about the chase.
He's either getting cold feet and you should just chill around him and reassure him. Perhaps even talk about it and explain that you're not about to marry him off.
or...
Its just not good for him. He might have either found someone else, actually doesn't want a relationship or he doesn't like you as much as he thought he did.
Either way don't let him trample on you or use you. Perk up that backbone and say he is either going to go out wth you and actually be with you, or he can sod off.