In each of these fics, Giles finds comfort (if only temporary/sexual, in some cases) in Ethan. You can't always get what you want, but if you try sometimes...
Listen to the Cemetary Trees, by
sadbhyl, NC-17/FRAO, post-Passion.
Paid In Full, by Laura Smith, NC-17/FRAO, pre-series, post-Eyghon.
Freedom, by Rari Cross, R/FRM, post-Grave, goes AU.