You might ask her what she thinks and ideal marriage looks like, what it contains, how the people treat each other, etc.?

Ask her what she thinks your idea of an ideal marriage looks like?

Ask her to verbally visualize what and ideal marriage between the two of you would look like.

Ask her what skills, experiences she might need before she can perform/be like she should be in her ideal marriage and what you might need.

Perhaps share with her some of the ideas of Schnarch (self-soothing, differentiation, no one is wrong), some of Chapman (5 LL) and that GAL (self improvement) helps improve marriages and see if any of that might help her get to where she wants to go.

Your insights are good, except the issue is not sex. Sex is a symptom, not the problem in my opinion.

>43 years of marriage--My wife and I are now closer than we have been in decades. I believe that my SSM is over.