I had a low sex drive before getting married, but not nonexistent. It's not him, just sex in general seems too much work for a small chance of enjoyment. It doesn't hurt, but so rarely feels good enough to keep trying. Same issue with previous relationships, but they never turned into marriage.
Do you have difficulty reaching orgasm?
Do you masturbate, ever? Have you ever regularly masturbated? How do you feel about masturbation?
When you try to get yourself in the mood, what goes through your mind?
You say it just goes away...what do you think is happening? Do you feel negatively at that moment, toward sex or toward your H?
Do you feel like he pressures you?
Do you think your husband knows his way around your body? Is he paying attention to your feedback? Are you giving him feedback?
I don't think there is something wrong with you, necessarily. It could be a LOT of things none of which are indicative of something "wrong" with either one of you.
What do you know about responsive desire in women?
How well you orgasm also plays a key role in your enjoyment of and desire for sex. If you're not getting there, the journey seems like a waste of time.... so getting there is kind of important. Have you heard of this web site? Www.omgyes.com
You should check it out, alone first. Once you've determined if the information is useful, share it with your husband.
The trouble is not that women don't understand men...men are fairly simple. The trouble is that women don't understand themselves!!!
Learn thyself woman.