In my future-of-sexuality editorial a couple months back, I lamented the lack of (among other things) homosexuality and bisexuality in human-future-in-space sf.
Just encountered an excellent example of what I was looking for: Geoffrey A. Landis's "At Dorado," published in Asimov's last year and reprinted in Hartwell/Cramer's Year's Best SF 8.
The protagonist is a woman who lives on a space station and whose husband (Daryn) is a starship sailor. She's worried that Daryn might have been on a ship that was destroyed. She talks briefly with a young man, Tayo, who also lives on the station, who's worried that his lover might have been on that ship—and her first momentary reaction is to worry that Daryn might also be Tayo's lover. It doesn't bother her in the slightest that that would indicate that Daryn was bi, nor does she react at all to Tayo making clear that the lover he's looking for is indeed male; what bothers her is only the possibility that Daryn might've been cheating on her.
All this is in passing, a minor incident that's thematically important to the story but not a major plot point; just casual, which neatly makes clear that homosexuality and bisexuality are ordinary and unremarkable in the world of the story. Nicely done, all the more so because Landis could just as easily have made Tayo female and thereby kept everyone straight.
I like the story as a story, too, btw; a little bit predictable, but good anyway.