GaryB,my husband and I are in our mid-60's live a relatively active lifestyle,love the outdoors,but were we to adopt a dog,he would definitely have to be older.
There are thousands of loving grown dogs,who for no fault of their own end up in a shelter.
You and your wife should visit a few shelters,meet different dogs,maybe even take them for a walk,if allowed and you would see for yourself,how grateful they are for any attention.
Maybe you would even fall in love.