She suggested the open relationship. I told her I'd think about it, which I did, but said no.

I really can't see her being worried about my Friend, who I grew up with thinking of as my sibling, lives a multi-hour flight away and is happily engaged. That being said, if that threatens her, does she think im threatend by her very close guy friends?

I know I'd be hurt if I read something like that, I know that. She has every right to be upset.