I am suprised the game does not support the concept of polygamy. Ok it doesn't fit the moral code of modern society we have now, but the world view is different in the game.
As a soverign of a country, in a land devasted by disaster and low population, it should encourage bearing of offsprings and, polygamy in the old days is the way for the rich and powerful to do just that!
Yeah polygamy happend alot in our own world history. However this isn't just a case of the whole of civilization being decimated is it, the land is dead and you cant grow much food so population boom would mean starvation.
Back on topic:
Yes it would be nice to be able to re-marry if your wife dies, a period of mourning or something would be a more reasonable penalty for letting your spouse die, where in you loose 50% of your stats or something for 10 turns and can't remarry until then. BUT you have to have the ability to remarry otherwise you just get cutoff from a major part of the game for a fairly easy error to make.
