Good morning from Texas! My family set-up is: my father, my mother (his wife), his “main” girlfriend and 2 “secondary” girlfriends which get changed usually every 2-3 years. Yes, we all live together in the same house - though it’s a big house - so it doesn’t feel crowded. It’s not a religious thing at all, we’re atheists.
This is not polyamory. This is polygamy. They’re pretty much opposites, because polyamory is about multi partner relations that respect the needs and wants of all of the participants.
Polygamy on the other hand, is only about the freedom of one person (usually a man), and actively restricts the rights of the other participants.