From your description, your physical side works, since you have had sex in the past, and this lack of sexual interest is due to your mental side. This is not really a problem since it is how you react, or rather, don't react. You are a normal guy if this is your normal, so carry on with your life. However, if this is something that you want to pursue, try visiting with a professional counselor who may help you get more answers.
I don't feel normal at all. My family thinks its strange that I'm not married or have kids since all my siblings do. I can't explain this to them ... I wouldn't even know where to begin.
I'm already seeing a counselor and we have discussed it, I think even he's dumbfounded by this. It just kills me because I have passed up on some really great women in college and one that I went out with for about 8 months who was very sexual and was worried that I didn't try to have sex every night ... which she definitely would have ... I think she though I was gay. She ended up dumping me.
I would like to get married some day, at some point I did really want kids but with this mind set I don't think its going to happen. Sometimes I get his on by women and do not realize it but when i'm told that is what was happening i'm like "oh well." There was a woman in college that had a HUGE crush on me, all the signs were there ... we went camping and shared a tent at her request but I didn't think anything of it. years later I was told that ... I've let so many great girls go by ... have a lot of regrets.