(on the woman’s part) the willingness to actively consent to and participate in such a circumstance.
This is what I take issue with. I have done little research but it seems that in the old Hebrew culture, polygamy was not rampart but more or less like we have with the Mormons in America. There was some who practiced polygamy.
Fast forward to today and we see the Muslim who also view it as a part of their faith. Many girls are not allowed education, even basic education and are sold(for cattle or goods) as early as 11 or 12. I don’t see a willingness but more a coercion.
As I don’t know what goes on in these relationships, I would assume we are talking only about men having many wives not the reverse and/or these relationships did not also involve women with each other.
I guess from the old testament, Abraham did have a concubine and King David certainly had many wives.
King Henry VIII tried to do the same, one reason being he he thought his kingdom was lost without sons.
I don’t understand what would constitute a moral reason for making it valid. Would the situation in China with 27 million more men do it but again I think we are only talking about men taking wives.