I had to respond here. Have you asked him if he is A SEXUAL, meaning someone who doesen't need, desire, or want sex!
These types of people don't choose to be this way, anymore than someone who is straight or gay! to them, the way they feel is normal.
These people do still fall in love, have emotions, also some if not all still like affection, but just do not have the desire or need to carry the affection onto sex!
If this guy is A SEXUAL, than he should already know he is, I am assuming that because you have stayed, he probably feels you have accepted him for how he is, without him having to announce his sexuality.
If he is A SEXUAL, then he probably can't understand or identify with your need for sex.
This situation after six years probably won't change, as if he had some problem with sex, if he missed having a sexual relationship, he would seek help.
I feel sad for you here, and I think maybe at your young age, you should start to think realistically about your future! You shouldn't feel guilty for wanting what afterall is very normal.
Best of luck