Take my advice with a grain of salt -- I definitely do not have all the answers for myself and can't pretend I have them for you.
A few thoughts, though: my first reaction is wondering what is going on with Bee. Does she want this kind of setup? Is she gaining anything from being poly, or does she just feel like she is giving up part of her husband? It is not necessarily your responsibility to care for her and give her what she needs, but throughout your story I was left wondering what the heck is going on with her.
Second -- I may be way off here -- I get the sense that you want to be considered co-primaries with Bee, but (I am guessing) you are reluctant to say that because Jay is not going to go for it.
I just want to encourage you to figure out what you really need, and advocate for that. You may be able to get it from this relationship with enough communicating and adjusting, or you might not. But if you don't identify it and ask for it, it's definitely not going to happen.