Dear Uncle Bill,

Dear Concerned,
Well. You should talk to your wife about this first of all. But I hear that she is a good listener. You may have a head start on this if you already vacation in a more sedate fashion, say on a quiet lake in Maine. She may not notice that you don't jog to the store for a morning snack when you never ever did that anyway. For example. So you are a lucky dog.
For some, this is a serious consideration and age does not need to be the factor. Sometimes because of health, or whatever, one person is much more something or other than before and adjustments have to be made. At some point, I can guarantee you that one person's health will be much worse. No fair hoping for some tragedy that takes you both at once. Conditions change and people change, but that is a challenge and a joy, not a sentence. I bet that if you look back on your life, you would be able to identify several revolutions that took place in your life together that you survived. I mean the family thing is no easy burden on a relationship and you got through those changes. Challenge the empty visions of simply sitting on a rocking chair together until you both croak from boredom at the same time. It's just fine if someone is out doing the things and someone else is not.