The bad thing is my wife really has no desire to go other countries so I may have to go solo. She would probably go if I really wanted her to I guess.
I think some people make the mistake of thinking that "foreign travel" means museums and cathedras. "Well, I hate going to museums and cathedrals here at home, so I would be miserable on a trip."
Forget the museums and cathedrals if your wife does not enjoy them. What does she enjoy at home? Crafting fairs? Flea markets? Golf? Laying on the beach with a fruity drink that comes with a paper umbrella?
Then, do exactly that in a foreign country. There are plenty of crafting fairs, flea markets, golf and beaches outside the US. I am good friends with a German woman who LOVES any kind of crafting fair or folk art exhibition.
My own foreign travel:
1. Mexico age 15
2. USSR age 24
3. UK age 34
Then, I got a job in international marketing and went all over the world, mostly by myself. I visited several foreign national capitals before I ever got to Washington DC. (Mexico City, Moscow, London, Madrid, Wellington, etc.)