So it's cool with Larin that the male love interests are himbos and you can have sex with a bear but a threesome with the two best women is taboo? I sense hypocrisy, double standards and self-righteous bigotry.
I think, what Silver meant was, that polyarmoury is not about having threesomes necessarily. It could be, that you are in a relationship with Shadowheart and she or you have another relationship with Karlach or Halsin or someone else. It does not necessarily mean, that you can have a threesome, that's a different thing.