I found it!!!!! It was
Balancing Act by Brynn McK and can be found at fanfiction . net.
The summary is:-
Can a vampire without a soul find redemption? And can the Slayer ever really love him? Angst, drama, Scoobies, minor brain surgery, with a little humor and a few warm fuzzies along the way. Buffy/Spike, of course. COMPLETE.
Spoilers Through As You Were, though we can probably assume this all takes place after Season 6-all has been resolved with the Troika, Xander and Anya, Willow and Tara, etc.
My heartfelt thanks to those who have been looking, the people on this site are just amazing!! You all deserve your own Spike!!

Sarah