Well, you didn't say how long you've been married or how your sex life was prior to this denial phase so its hard to say if she's getting some onthe side, thus just a wonderful cheating slut, or if she has a really lousy sex drive and/or she was used when she was younger and so just doesn't like sex.
Goddess I hope its none of those last options and she's just a lovely cheating hotwife.
I'll go with that option and suggest you talk w/her ~ turn it to your full advantage and become a real acknowledged cuckold.
And if she' not cheating and yet only wants to let you masturbate while looking at her then there is a good eliminate of control going on for her. Just direct her to few areas to read to help her and encourage her to explore her Domme side and you will both have a richer and more fulfilling relationship on so many levels.
It does take time and patience and a willingness to step out there. But you married this permister and if there is anyone whom you need to be upfront w/about what you want and need emotionally and physically its this one permister.
Good luck in your exploration.
I will keep my fingers crossed that you have a very promising cuckoldress on your hands.
I am a truly blessed Lady who is still learning and enjoying myself immensely at my hubby's expense. :) I love a cuckolded husband.