I was once in your position (no pun intended)in my previous marriage. I was the wife who didn't want sex, never wanted it, never desired it. Now, in my current marriage...I am married to a man who is the same way, and we are now slowly working towards better things.
Anyone going into this though I will tell...it IS a slow process. There are no quick fixes, no magic buttons. It's going to take time, patience, perseverence, boundaries, and consequences...and tons of introspection. It's really hard to take a tough stance in your marriage, it's tough to draw that boundary...but it can be done lovingly.
