Their final year together, they'd planned to dress up for New Year's Eve and paint the town red. Spike had kept clarifying but not in blood. It had been funny at the time.
The girls insisted on putting up a tombstone. Xander never visited it. Not once. Even if they had managed to gather the scattered ashes, he wouldn't have been in there.
Each year, on New Year's Eve, he dons his tux, carefully preserved for this one purpose. He doesn't go out. He turns on all the lights, making his apartment as bright as possible, so he can see the wasteland his life has become.