Mass Effect has characters with pretty fixed sexual preferences. Only a few males and females will enter into homosexual relationships.
Given how disturbingly artificial TES is, ESPECIALLY the NPCS, I question the idea anyone there is a "person", but that's a topic for another day.
What is on topic is how Skyrim just made any NPC the player can enter a romantic relationship with bi-sexual (or at least player-sexual), which I feel is a cheep cop-out.
I think the only games I've played with a gay main character (that weren't just hopping on the "Make every love intrest bi-sexual for inclusive points") are the Swordcraft Story games, GrimGrimoire and Fear Effect 2 (which was done PURELY for a love triangle over a love arrow...).
But I agree that having every character with no sexual or romantic preference is hardly much of an improvement over having all characters be straight (which is at least a realistic approximation of a medieval society).