as for ur example: remain childless, adoption or get divorced before remarry-ing. I know the family will want him to re-marry or give permission for this, but he needs it from his wife. Some women are strong enough to handle this (stronger than men, men could never share a wife). so mayb then its a possibility for the people, who dont have a problem with it.
I dont think there is any reason for polygamy.. women can also be treated and taken care off as ‘sisters’ in bad times, men dont need to marry them imo…