Pablo Neruda's poetry always speaks Spuffy to me. This, from "One Hundred Love Sonnets: XVII" seems to beg for a story that happens sometime between s6 and s7 in some way but my muse has suffered as late and I'd love another writer to run with it (I may eventually tackle it myself but don't want to wait). The entire sonnet is inspirational for Spuffy IMHO.  https://dmitrimatheny.com/blogs/dima-s-blog/posts/60963/between-the-shadow-and-the-soul-by-pablo-neruda

The part of the sonnet in particular that made me want to leave this prompt is:  "I love you as certain dark things are to be loved,in secret,between the shadow and the soul.”   Although many other lines are inspiring as well.

Sort of a Buffy POV where she realizes she actually did love him in S6 even when he was her "dirty secret". 

Can be angsty or a fix-it... whatever. Could even work as a time-travel or so many other possibilities long and short. Just the realization that love, however messy, was on both sides even prior to the soul.