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.
I’m fairly certain only to my father. I never asked straight up, but I never saw them act affectionate with one another the way they do with my dad in my entire life, so… I’ll take that as proof.