I meant that she is ok with open relationship, but not interested in poly though? If that wasn't clear.
But.. how do you come that conclusion? HOW is she up for an open relationship? The word poly or open is never even used in the game. You ask if she's up for ANY KIND of relationship with the other origin companions, and she says no because she wants YOU ALONE. If that somehow wasn't clear enough, then the following dialogue is: "In truth, I don't think I'd want to be your spare lover. I'd always want more of you than you'd have to spare. Better perhaps to bow out with dignity."
That doesn't just refute poly. That refutes open. She does not want to share you, casual or not. Case closed.