I would think an obvious example is Jaida Jones and Danielle Bennett's Havemercy, in which two of the four main/POV characters are gay, and eventually end up together. I'm not sure I can comment on their relationship, although I thought it was sweet, but I thought overall that book had enormous race and gender issues, which saddened me as I think they are fandom-ers gone pro. Some of the race stuff is because there is a war on, so the "other side" (which is modeled on Japanese culture, I think) is of course all evil, inhuman heathens. This gets corrected for some in the second book (Shadow Magic), which is set after the war ends, and has two protagonists who are from the Japanese-style culture, but I thought in Havemercy came across as these-are-the-authors'-opinions, rather than these-are-the-characters'-opinions. And I don't think a single woman in either book is viewed as/treated like/written as a human being.

...having now eviscerated both books, I will say that I really did enjoy them anyway! *laugh/sigh*