Eh, don't worry about it. I'm in exactly the same boat as you are (with the caveat that I don't care). You're just experiencing the deep-seated need for physical companionship and (eventually) reproduction. I am too, I just recognize it as a base need and dismiss it as ignorable for the moment.
In my case, it's mostly self-inflicted. There are plenty of attractive women who consider me attractive and some of them have even approached me. I turned them away for a variety of reasons, not least that I refuse to have sex with anyone I'm not willing to spend the next 18 years, 9 months supporting (I don't care how unlikely a pregnancy may be, I don't take chances.).
There have been five women in my life whom I have found sufficiently intellectually stimulating to consider a relationship with. All five of them failed my acid test (a series of values they must share in order to be happy within a relationship with me; yes, in order for them to be happy, and yes, the acid test varies from person to person) and therefore I remained quite happily in the "friend zone."
There is no reason to ever be in a relationship that you know either party will be unsatisfied in and, if you haven't found anyone sufficiently interesting, you haven't found anyone sufficiently interesting. My uncle went almost 50 years without being in a relationship and, when he met his fiance, it took 3 weeks to know, beyond a shadow of a doubt, that she was right for him.
To be able to maintain a relationship, you must first understand both yourself and the other person. I do this within the framework of the Myers/Briggs Test (obviously imperfect, but workable and, honestly, I'm smart enough to recognize when it fails), but other people don't necessarily do it at all and I'd like to think that everyone would be a little happier if they did.
