Why don't I mind that hes using me?

I've been fwb with this guy for about a year. We're both in college and he says hes just to busy, heart-broken, scared, etc, to have me as his girlfriend. Mostly it's that he gets and doesn't have to worry about anything else, not that he'd ever actually admit it but whatever. We use both the pill and condoms to make sure nothing happens, at least as sure as we can get. We have been very off on and on, me leaving him several times to try and pursue a real relationship with no luck and then returning to him. We are very fond of each other and enjoy each others company but it just hasn't, and probably won't, develop into anything serious. Yet I don't mind. Being with him, though off and on, has been the longest and most exciting relationship I've had even though it's not really a relationship at all. Is there something wrong with me? I know I can't know if he sees other girls (he says he doesn't) and I can't ever go on real dates with him. I only see him once or twice a week. But I like being with him. Is this wrong?