Shaw's "prose sequel" to Pygmalion is still the characters' canon future.
The musical's final scene between Eliza and Higgins might be a Maybe Ever After, but that's all it is; a maybe. Nothing indicates that they'll actually become a couple. It's still more than likely that Eliza will marry Freddy and open a flower and greengrocery shop with him, as Shaw wrote, and that she and Higgins will just be Vitriolic Best Buds. The ending just signifies their reconciling as friends. Henry Higgins isn't straight
"Confirmed bachelor" has been code for gay for a very long time, there is plenty of Ho Yay between him and Pickering, and he never really does seem to show any actual romantic interest in Eliza. As the characters in Will & Grace put it: Two confirmed bachelors in their late fifties whose idea of a good time is dressing Audrey Hepburn in fabulous Edith Head outfits? Oh, they were gay, my friend. They were gay.
Also, if you accept Word of God from Shaw on Pygmalion as still applicable, what he said was that Higgins was too much of a mama's boy to be romantically interested in women; Higgins being asexual also makes perfect sense for his character. He clearly likes men, but just not in *that* way.
