Stiles is kicked out of the pack, steter fic.
Derek is the Alpha and dating Stiles but decide it would be safer for him if he is kicked out of the pack. Stiles decides to move away and goes to college. Peter either leaves with him or goes to find him and they start dating and build their own pack. Stiles goes back to Beacon Hills after many years have passed to see his dad and Derek wants to get back together but Stiles does the Peter reveal with ensuing drama I'm sure. I remember the author referencing a love poem or song throughout the fic for the steter relationship that had something to do with a pillow and your lovers head or something like that.
I've been looking for this one for a while, thanks anyone who knows it!