The fact is that your argument is nothing but headcanon and has no basis in reality. It's not even interpretation, it's headcanon - completely made up in your head. You have given nothing concrete to support your argument. You have given subtext that you've imagined have any meaning, that just doesn't have any. You add things to the game that aren't even actually in it. And 99% of the people here disagree with you.
Until there's a scene at the end of the game, where SH says they should include others or are actively already including others, then her and Tav are in a monogamous relationship canonically. Because optional porn doesn't change the ending and adding things you imagined doesn't count.
