WOW. Sounds like the political differences just reared their heads.
I can't understand it either when one affiliates with a group who would happily shoot them on sight. I also see your points about the bf. I am the new third in the triad of a long term married couple who were never poly but had occasional romantic friends join their bed over the years. I don't know if I am projecting- probably- but I don't get the equal standing ideA the dh promises I feel it's insulting a bit to the dw.