Think about comic book fans for a moment, and "superhero" comics fans in particular. We're all familiar with the stereotype. There's a reason for that stereotype: it's largely true!
So, what sort of gay relationship will appeal to single guys with limited social lives who spend as much time as they can living in a world of fantasy? What sorts of gay relationships do guys like this fantasize about? Most importantly, how can DC use a gay relationship to drive sales?
I think the answer is obvious as to the most likely gay superhero candidate: