You are getting lots of great advice. Why don't you do something really drop dead interesting as a way of declaring and defining the new you?
May I suggest you enroll in something way out of the ordinary as say the UW experimental college if you really are in or near Seattle. https://depts.washington.edu/asuwxpcl/
How about signing up for the couples massage class (they will set you up with someone), the inexpensive global volunteering travel class, Flirting 101, Salsa dancing, Tango dancing, or Figure drawing. Any of those things would make you a much more interesting person and someone who is not the same old you. Your job is to GET A LIFE by building a new set of skills and experiences. You need to focus on you (and your development); not on what you might be loosing if she chooses to leave you.
>43 years of marriage--My wife and I are now closer than we have been in decades. I believe that my SSM is over.
