And, as of recently, Selina Kyle, aka Catwoman. In fact, Batman Incorporated
's first issue implies they have sex before heading out on a mission. At least, that's my interpretation of the scene in which Bruce is lifting weights in his underwear and Selina, also in underwear and a sportsbra (and boots!) straddles him and meows at the idea of having some free time before having to head out.
And while some might point to the more recent and overt scene from Catwoman
#1, I use Batman Incorporated
as an example because it was written by Grant Morrison, himself.
I chalk it up to Morrison not meaning "gay" as literal, but more figurative (though the idea of using the term "figurative" in regards to a piece of fiction boggles my mind). As was pointed out, he's not the first to suggest that some may find something sexually deviant about dressing up as a hero and fighting crime.