My best friend knows and one of my brothers (and his wife) knows. The best friend worries a little about it thinking that my wife might decide she's not OK with it after all and I lose access to my children.
My brother is not down with it and refuses to discuss Susan ever. It really hurts because I've supported them in lots of non-conventional thinking. And if his attitude is like that, I have no idea how I'd ever tell my parents. Also, Susan and Kay would both hate it if I did.
Me: 40 straight male in a V with
Wife: Kay - mono female - married 18 years
LDR girlfriend: Susan - poly female - 3 year relationship
Stakes - very intimate friend