I am a 56 yo never married female. I have met many women in your wife's situation and it continuously amazes me, yes Amazes me, that these women seem Clueless of the impact that this behavior/attitude has on the marriage.
Having been in a secure relationship for so long, many of these women feel justified in calling upon the need for accommodating MY FEELINGS, MY NEEDS, after "so long." Which truthfully, though often justified, comes at "a bad time" for their other half. Meaning, as women enter Menopause, men enter the Mid-Life Crisis phase of their own life. Coincidence? I don't think so.
As she becomes more frigid, his sexual needs become more demanding. Truth be told, he is undergoing as much of a mental sexual change as she is a physical one. And as a function of their own aging process, each is feeling the need to accommodate any sexual demands that they've not felt were adequately met to date. For her, it may be Leave Me the Hell Alone and for him it may be Give Me More, More and More and by the way, Be Someone Else because my familiarity with you has become, frankly and disappointingly, Stale in bed.
It seems to me that most (not all) people enter a marriage understanding that the personal needs of their partner is paramount (because they love them so much) but it's also, in the long term, a Two Way Street. Meaning, that from time to time, over the many years of the relationship, one person's needs will outweigh the other's. And because it's a long term commitment, that prioritization of one person's needs over another's can go on for some time, obviously making the other, at some point, resentful and in many cases, more than interested in taking action to rectify the Needs Balance.
I believe that the peculiar yet undeniable timing of Menopause:Mid-Life Crisis is why a lot of marriages suffer at least the risk, if not the realization of divorce despite many happy years together. In my mind, it's a cruel and unfair reality that as she loses interest in sex, he begins to feel the panic of not having Explored More at a time when his body is aging and his appeal to women he finds desirable, may seem to be diminishing. Both individuals likely feel that this is the time to take action. For her, it's asking to be Left Alone, for him, it's expecting that his needs be met by either her or understood that it will be with someone else.
You asked for advice. As to your specific circumstances, as described above, you both lead stressful lives right now and you seem to love your wife and want to continue your marriage with her sans the Sexual Isolation you've been experiencing. Consider this: one day, in the not too distant future, you will not have the same pressures on your lives that you have now. Is she the one you want beside you then? Or do you see your life (realistically) different? If she is who you want, then work with her on this. It sounds like you have done some of that, by attending counseling, for which I commend you. I am sure that was difficult, but in my opinion, marriage contracts deserve it.
I stated at the outset of this (very long) message, that it's been my observation that women are clueless to what withholding sex for so long means to a marriage. I also stated that it unfortunately comes at a time in the individual's lives when he and she experience very divergent sexual needs. You must talk and come to an agreement about how you will negotiate this period of your lives together. If you cannot negotiate a common resolution and you need to find your own solution, be prepared for the emotional and logistical consequences that may follow, including the feelings, reactions and behaviors of your friends and family.
In the end, it's your life and you need to make your own decisions. Consider what is most important to you, not just in the short term, but in consideration of your life in the 20-40 more years of your life that you have left to live it. You will leave this earth alone, you need to be satisfied with the experience it held for you as an individual as well as who you are to the people you love and those who love you. The decisions you make are purely your own, best of luck to you.
I truly hope these words were of some use to you.