I have to admit that most of my information about polygamy comes from Biglove on HBO. And on that show a man is legally married to one woman. And through some ceremony that is not recognized by the state, is "married" to other women who all live together as a family.
How was that ever illegal? And even today, why is it so bizarre? To me, the big downside is the cost
But if 1 man and his wife want to have other women they call wives living with them, why is it anyone's business?