Because it's inconsistency or my "headcanon" fling(Him freaking out from the word "relationship" kinda supports that, not to mention inconsistency around other companions, as SH won't agree for Tav to be with anyone else, she cuts it instantly, without any elaboration). Thats why I think this way. Rabbit headcanon is wine dialogue hinting at "poly in the future maybe" and her wanting "nesting partner" first(thats why in his headcanon she refuses poly as she sees 5 origins to threaten her relationship with Tav). I disagree, because to me its obvious that she just wants you alone for that bottle and first date. It doesn't end up in sex aswell. So is her poly proposal denials, there is nothing that indicates her wanting "nesting partner", if you propose Gale to her as poly partner, there is "why let monogamy get in our way" line - she refuses again. Wyll response, etc. I don't overthink it. He just reads this way with his headcanon and its consistent in all 3 acts. My headcanon lets story by sorta consistent(I know that you disagree) and let her relationship with Tav be "open mogonamy" more or less. We agreed to disagree, everyone has right to read situation how they want basically.