Let's be honest: while the vast majority of queer folks are comfortable reading about straight characters, a lot of straight folks aren't comfortable reading about queer characters. Consequently, in genres dominated by straight male authors and straight male readers, gay characters simply don't exist. Or, if they do, they are side characters; their relationships fail; their lovers die; their sexuality is a constant source of pain, and they rarely (if ever!) are shown in normal and healthy relationships.
There is some protection in the romance genre, where m/m literature is steadily growing more and more popular. But, unfortunately, not among other genres.
Lynn Flewelling's books are the exception.
She's well known for her award-winning Nightrunner series. The books aren't what I'd call romance -- they're hardcore fantasy, complete with wizards and swords and dragons -- but they do feature loving gay couple as the protagonists.
Let me stress how awesome this is.