Or, there are same sex couples out there, and they just don't make a big fuss about it. An auctioneer, the blacksmith or anyone, who knows?
WoW is a fantasy game. It doesn't have to be you that is in the world, just the character you play. There's men playing female toons, women playing male toons and no shortage of humans playing as cows. See the world through their eyes, not your own.