So sorry you are having such a rough time but I don't like this "begrudgingly giving" sense I get from your SO. Sounds to me like there would have been problems in your relationship with or without this happening over Poly.
If she won't even discuss something that is obviously important to you then I don't think there was much of a future there to begin with...
I feel frustrated. I feel somewhat I was lured by the kink scene and all the sex talk.
I think you were too my friend I have known several people that have fallen victim to that ploy and it always ends badly... *hugs*