I think there's a bit of thing where the less toxic the people, the more discreet they tend to be. I certainly wouldn't let anyone who had only visited my house a handful of times know I'm poly. That's only something people I would call friends would know. I also have pretty strong boundaries around not having secondary partners who aren't specifically looking to be a secondary partner (usually because they already have a nesting partner themselves).
It's also one of those things where most of the people I interact with IRL are all cool chill and reasonable people and then I go to nearly any online space and everyone is freaking insane with really toxic dynamics.