martinsnow parent
It's perhaps the dish that caters most to westerners. If you ask my wife it would be papaya salad, though fermented fish can be strong for some.
There are Kaphrao boom in Bangkok for last 10 years or so. Previously it was cheap, fast food dish that is common in central Thailand, but it has since been researched, experimented, and elevated. If you wife aren't from central Thailand and hasn't really been back for the past 10 years she probably doesn't really connect with it.
Somtam doesn't necessarily have pickled fish in it. Somtam Thai is relatively mild if you order/make it without chili - it's mostly just sour.