If you liked Cuzco, I think you have some interest in history (maybe not European history) and you certainly find places in Europe which could be of interest to you. Europe is not the same all over the place.
Taking your first point of interest, I'd suggest you could consider either Switzerland (stunning nature in the alps, hiking and other outdoor activities possible) or the Greek Islands (very relaxing in off-season). Santorini is a very nice place to spend some time with your gf.
If you want locals, who are different from the US, then you should rather go to places like Bulgaria or Romania, but you might not get in touch with them because of the language barrier.