(Gaaaaaay~)

Actually to be honest Theo is Demiromantic/Asexual (exclusively for Ethan) and Ethan is Homosexual/Demiromantic

So why the gay flag not the Demi one?

Well~ I think it says a lot about their relationship/personalities if you think about it~
Ethan being flambouyant and proud, keeping up appearances or being a massive gay icon, and Theo more than happy to go along with it as his boyfriend, even if he's Ace~