However, I understand from reading these forums that Wife Games are a very particular thing. How must I convince my wife, when my fiancée has transformed into one, to play Jambo and Lost Cities instead of the games we currently enjoy?
But the best way to convince her to play shorter and lighter games is to have children. They will substancially reduce the time you have to play board games.
This is exactly right. Not only will it transform her into a stereotypical "wife gamer," but it will transform you into a stereotypical "husband gamer," who dreams about longer, heavier games but never actually gets to play them. Ever. With anybody.
For example, my wife and I used to play Caylus. Now we play Blokus Duo.
(This is an exaggeration, of course, but only a little bit. And really, kids are well worth it. But enjoy the time you have now).