Ok - Big wake up call. If a guy isn't calling you his girlfriend, but his 'lady friend', this is a sign he doesn't want to really be with you, and doesn't love you. You are like a used beat up car -- convenient for the time being and fulfills his basic needs -- until he finds the more classy, expensive upgrade automobile of his dreams, then he won't need to drive you around anymore.
Do not wait around for a guy like this! The fact that you stick around and put up with this status, is enough for a guy to not respect you. He's likely flirting with other women on the side -- at work, or at bars, and doesn't want to feel bad/guilty about it, so that's why he doesn't officially make you his girlfriend.
Get a clue. If he isn't locking you down then stop wasting your time.
Why doesn't he want you?
You may not be the one for him. His timing may be off, or he's just too damn immature to realize how awesome you are. Whatever the case, don't feel bad! Tell him you are looking for a man that wants to be dedicated to you and stop calling him! Get some self esteem, woman!
Best of luck to the women of the world!!!!