I kept editing the above as my thoughts evolved on this but I think I'm done.
Not getting into who's dating who or what not because that's a different can of worms but Taehyung has tons and tons of friends some of who, oh, grab his ass casually. (Minho) This seems to presuppose that Bogum and Tae did date at some time but there's absolutely no proof of that anywhere. They have chemistry and are close friends, but that's true of lots of people and Tae. He's got chemistry with rocks. To follow the logic that he's playing exes against each other you have to start with the belief that Bogum is more than just a friend, and that's a leap. Possible but no proof or solid receipts except two attractive friends taking pics together.
Looking at the possibility Tae was with anyone inside BTS, would it be a successful relationship if that person didn't understand and accept what a social butterfly he is? Presupposing jealousy is very popular in the shipping world, and I get the appeal but I think the danger is that it makes the actors in the story seem childish and remove the nuance that make up real relationships. Not that you're necessarily doing it but it happens a lot and is part of the whole thing and part of what turns shipping into fantasy and ignoring the real people behind it. That's hardcore shipping, and is different than thinking real LGBT idols are maybe relationshipping.
Of course open relationships exist as well which shippers don't tend to acknowledge.