What happened between Buffy and Xander stayed in the dark corners. never bleeding out into a world that was already too complicated. On those lonely nights they fed a mutual need for companionship, always knowing that when morning came nothing would be different. Their lives already contained too much murky inbetween. This was the one simple thing they had left.
The one thing that made Buffy Summers so different from the rest of the slayers throughout history was that she had been able to achieve some semblance of balance. Somehow she had managed to play back and forth between the world of the Slayer and the world of the normal human being. Her strength came from an intense drive to restore that tenuous equilibrium when things got murky. Normalcy was her most precious possession. At least in the beginning anyway. Now things were always murky. With so many thousands of slayers out there the black and whites she had fought so hard to keep apart were turning the world an awful, confusing, uncontrollable grey.
That was another thing Willow had been able to do- make the grey okay. In fact she had made it look good. Somehow, when she was around, Buffy could deal with the inbetween because she knew Willow understood balance better than anybody else in the world. Her life had been a constant struggle between an evil that brought necessary power and a good that came with damning weakness. Through it all Willow had been there to link them to both worlds without letting one consume the other.
And now she was gone. Maybe forever and there was nothing they could do but stumble through the fog of grey by themselves.
Even now, with her life completely unrecognizable to the one she had known in the beginning of all this, there were still remnants of that duel life she had once lived. In this world of inbetween it had become her downfall. That tragic flaw that ruined all her relationships and made her seem like the cold killer she so desperately hoped she wasn't. She just couldn't shake that mercurial way of life completely and that meant that most people couldn't get close because they couldn't keep up. Spike and Riley had represented polar opposites. Too much of one world and not enough of the other- just far enough away for her fingers to graze but not close enough for her to grasp. Angel had come the closest but he was forever fighting his own battle for balance. Maybe he always would be. Even Dawn would be forever too human to exist on the same plain as her sister. Eventually it always came back down to Willow and Xander
And now just Xander.
The biggest surprise was that the sex hadn't ruined their friendship. People always told you not to get involved with your friends like that. They warned that it'd screw things up but some how that hadn't happened yet. It was a testament to their mutual loneliness that they had been willing to risk so many years of dedicated friendship. More than friendship now, it was dependence. But like Willow, Xander had danced between the two worlds right alongside Buffy. Like Buffy he had been a creature living two lives utterly different from each other. And he too could not unite them in himself even if they were united in reality. The sex happened in some other world of physical need, although not necessarily for each other, that somehow stayed completely separate from that other world of destiny and duty. It just happened and, in order to keep the grey at bay, they let nothing else happen to make it complicated.