Nobody's assuming she prefers that relationship. She says she prefers that in act 2. Never does she change her stance on that, except according to you, offscreen. And for some reason only for these two interactions. After that she's all back to being mono for the rest of her main story in act 3.
I think people in this thread are assuming that SH prefers monogamous relationships. Yet no conversation about monogamy takes place on screen and three poly relationship dialogues do happen on screen. So . . .
