My wife and I been together 3 years she going through menopause and says she wants out. What can I do?

I was married 30 years when my wife died. But, was married only 7 yrs before that, ending in divorce.
It's really sad when this happens, but it's life for about 1/2 of all marriages in America.
I don't really think there is anything you can do about it, if she really wants to leave. You can get over it, if it happens, and it will take some time. I do wish you the best, and good luck.
I also think that if you are both willing, please go talk with a marriage counselor. There is no guarantee, but it could help talking it out with a third person.

Let her go.