Read this ages ago & loved it, but lost my link due to computer issues.
Buffy & Spike are togethe & claimed. They are fighting a snake like creature in the desert. It catches Spike by surpries & decapates him. Buffy kills it and is transported back to say good-bye to everyone before joining Spike in the afterlife. Spike is met by an Angel who wants to take him on, but he's determined to wait for Buffy and so tells her a story his & Buffy's love story to keep her attention while waiting for Buffy.
Thanks for the help. It's one of those "I love to re-read it" stories, but my brain just can't remember the name/author. | 
