I just wanted to remind you that chances are it has nothing to do with you. Do you know if she's sexually attracted to ayone else? When I first got married I was not sexually attracted to my spouse. It was really hard cause I felt like I was punishing him for my issues. Reasons I wasn't attracted: A. I was raised with nudity as an art form and natural and not to be seen as sexual. So basically my mind was programed to not view things as sexual. And B. I was a virgin and sex HURT! It's kind of hard to get over that. Now I do see him as sexually attractive, but probably not as much as most. And although it doesn't hurt I still have a very low sex drive (which my doctor warned may be caused by my meds which I don't plan on quitting). I also struggle with my brain completely shutting down and shouting 'no' whenever my spouse is the one to make the first advances. Once again, probably due to how I was raised. Overall, I know this probably hasn't helped much, but I want you to know there can be a lot of factors. I think the best thing you can do is be patient and be in counceling. Time will help her, but only when she's willing to work at her issues (and even though it may not seem like she is at times, trust me, she is). As woman we are trained that it is our "job" to take care of our husbands needs (including sexual) and most women experience incredible guilt when they feel unable to meet these needs, which obviously just enhances the problem.
I'm sorry I can't be of more help. All I can share are my experiences.

Good Luck