Hey,
I'm really sorry you're going through this right now. I'm sure it is VERY diffcult.
I'm probalby not very qualified to offer advice on this subject -- but, I thought I'd offer my two cents from a different perspective than the others...
I've been with my boyfriend for over three years. We broke up for 6 months in the middle. But for the majority of the time we've been dating we were long distance (went to seperate colleges). What I've noticed is that when we are apart for long periods of time and then suddenly together for only a little while, we have built up being with each other so much we can't wait to have the other in bed! Now, over summer breaks, we relax A LOT. We've subconsciously realized that we can now have the other whenever we want, so we dont feel pressured.
So, what I'm trying to say is that there is a big chance that him not being intimate with you actually has nothing to do with you. He could still believe that you are the most gorgeous thing in the world and that he's very happy and very lucky to have you. And I'm sure he is still very much in love with you. The spark (and pressure) has just gone away.
What I try to tell myself every day when dealing with my issues (which I know are not the same as yours) is to forget about the past and to think about the present and the future. While the WHY is important, your husband may not have a tangible, solid answer. Try to move beyond this and think only about the progress you are making.
I hope this didn't offend you or anything and that I was able to help at least a little.
Best wishes

,
Ro