ygrec,
Just for some background - I want to let you know that my husband was physically abused by his first wife. It was many years ago now and in their case, it was a result of her drug use. He left for a work seminar and returned to find that she had taken the children and burned all of his belongings. His belongings were still smoldering when he came home. Abuse is not just a male or female issue.

Just a thought as it is so obvious that you love your wife dearly and do want to help her. Have you tried pulling her into a hug when she starts hitting you? I can sense that she feels let down because you are no longer in the position of being the provider. Though through no fault of your own, I suspect she is feeling that her life is turned upside down and no longer matches what she expected life to be. After 42 years of marriage with certain expectations and lifestyle, this has to be painful for both of you. But for someone of your wife's age, perhaps it is even more devastating? After all, think of what happened in our country during all of that time and how it affected people's way of life, expectations and finances...

Again, don't know if it will work, but maybe, just maybe pulling her into a hug that lets her know you are in pain as well could be a healthy move?

Wishing the best.