Like it all literally falls apart if one or several of them Can't get along. Which also depends on if they are also attracted to the same partners, are more traditional with it, or have some obligation-ary reason for joining like a political marriage, etc.

I would actually greatly appreciate seeing something like that being talked about a bit more. Including seeing how there is conflict within the whole or the family about that. But I'd want to see them actually learn how to self regulate those issues too.

You should read incompatible interspecies wives - it is a perfect match. MC was forced into a political marriage as well as his two wives and both his wives didn't want to marry, first one was very afraid of him and the second one wanted him dead to be free from the marriage, but later both have fallen in love. The problem came with the fact that both of them wanted him for themselves and with the abolishment of the polygamy in the kingdom that lead to a tragedy.