I talked to BF more about this tonight. He said his wife felt sad that the GF was hurting. He himself seemed rather puzzled by it, when he first told me of it, like, What got into her? I don't understand.
I struggle with this, because, to be honest, I'd think most women outside of the poly world, as their feelings for the boyfriend get deeper, are going to have an increasingly hard time coping with going home alone while their boyfriend goes to bed with his wife.
From my perspective right now, it looks almost cruel, at the very least thoughtless, to invite this woman into his world, being kind and loving and giving till her emotions are deeply involved, all the while assuming she'll adjust to this worldview contrary to the rest of society and everything she's ever grown up expecting, assuming she'll be quite happy always being the one to go home alone while he always has either her or his wife--and then being surprised when she hurts.
I guess I feel better having asked him directly how his wife felt about her very presence causing this woman pain, and I guess I'm glad she didn't feel smug or possessive (I kind of figured I was off base there), but feeling 'sad' also doesn't sit right with me. It seems patronizing and even hypocritical, to be part of bringing someone into a situation that's almost bound to hurt them, and then pose as the compassionate person who feels for that pain.
Maybe what I should be asking here is the broader question behind this: how wise is it to invite vanilla, mono people, with no experience in open relationships whatsoever, into a poly relationship?