I believe everything is kind of relationship of some unique color combinations.
I guess I've to decide how much i act and how much i leave to the hands of fate on the basis of attraction of those colors:).
Depends, how important is it to have that "title"? If he's treating you like his girlfriend and you feel like his girlfriend, then you probably are. But if you're concerned that he doesn't see it the same way, that he might still be seeing other people and not consider it an exclusive relationship that's a legitimate concern. You could always just ask him if he's seeing any other people and have the conversation from there about how you'd like to be in an exclusive relationship with him. It sounds like he's already there to me. Avoid questions like "so where is this going?", it's like man-repellant.
Say something to him. Hopefully he feels the same way as you. good luck :)