I know we've been told "most" companions are romance options, and everyone except Minsc and Jaheira has been confirmed as one. Given that Minsc almost definitely isn't a romance option, what about Jaheira? Is there any confirmation one way or the other? I can see arguments both for and against so which is it?
I don't know about Misnc and if he ever had a significant other but Jaheira is known to be married. I don't expect these two to be romanceable plus Larian has only shown Halsin and Minthara as romanceable outside our origin companions.
From what we know of canon, Jaheira is known to be widowed, but is not known to be married during Baldur's Gate 3. We also know from Baldur's Gate 2, where she was actually the canon romance option, that she was able to enter into a new romantic relationship very shortly after losing her husband. So while I can see lots of good reasons to not include her as a romance option, her past marital status isn't one of them. Minsc's only personal relationships in the previous games were that of being the guardian for his "Witch." Which is to say Dynaheir in the first game and potentially Aerie in the second. Neither relationship appeared romantic.
The main issue with a Minsc romance has always been his mental state. Whether he's actually capable of entering into a relationship and giving consent is debatable, so it's not surprising that many people think he isn't a romance option in this game.