I agree very strongly with BU. This relationship sounds damaging, dysfunctional and unbalanced. Poly should happen in the context of a strong, healthy relationship, whereas it sounds to me like this relationship shouldn't be happening period. It's not a matter of you two disagreeing on rules, it's a matter of her completely refusing to follow a single rule you've requested. How could you ever trust someone like that, and how could you marry someone you can't trust?
"She would find some hole in my argument and turn it around on my glass-throwing or name-calling, which, since they did happen, I couldn’t deny. I said, “You can’t distinguish safety from control.” So then that means I’m saying she’s stupid. And around and around."
She is making you out to be the crazy one and trying to use that to control you. THAT is abusive.
Throwing a single item, *once*, and not *at* anyone is not violent or pre-abusive, it's just immature, as you admitted, but not nearly as immature as her behavior. So you suggested she might be a sociopath. It's not name calling if it's true, is it? I mean, what kind of person who can understand and feel empathy would blithely stand their breaking up their friends' relationship like she did with that poor lesbian couple.
"Recently she admitted to some unsafe sex practices."
Did she exchange fluids with you before owning up to this? If so, she is disregarding not just your emotional health (ignoring all your very reasonable requests for respectful relationship behavior) and your mental health (trying to make you out to be the crazy, scary one so that you no longer trust yourself), but now also your physical health.
What won't she do? Why would you stay? GET OUT before you find out just how sociopathic she can be...
The major players. Me, 30ish bi female. Gia, girlfriend of 4+ years. Clay, boyfriend/dom. Davis, ex/friend/"it's complicated." Eddie, roommate & fwb.
The supporting cast. Eric, Gia's husband. Bee, Gia and Eric's toddler. Dexter, Gia's lover. Helen, Eric's lover. Izzy and Nikki, Clay's partners. Liam, Eddie's husband.