Could we get your wife and my husband together...... they could start a monestary.....lol.
Don't cheat!!!! Trust me, I know where you are at right now, my husband has every excuse in the world. The rejection and unwanted feelings you are experiencing are unbearable I'm sure, but what you will do to the trust you both have built would be more unbearable.
The first line of solving things is communication, if she can't open up to you maybe you should seek some therapy together.
Keep up what your doing and remember that a woman loves to be romanced. Don't romance for the purpose of just having sex, but do it so that she understands how much you care for her and desire her in that way.
Best of luck to you.!!!!!