*FOUND* Stiles returns to BH and he's kind of a mess
Looking for fic where Stiles left BH for years. Maybe not on the best terms?
He's is joined by an original female character who he eventually (maybe) marries. They travel around in and out of the supernatural world doing things. After a few years there is a conflict with another (bad) pack. The bad pack kills his maybe-wife who was also carrying their unborn child. Stiles believes that the child is killed too. He returns to BH because he has no where to go (possibly to bury the maybe-wife) and he's a hot mess.
Eventually he finds out that the bad pack that killed the maybe-wife was able to save and kidnap his unborn child, because magic. His child is then born later by a member of the bad pack. The rest of the fic is focused on his old BH pack fighting and getting the kid back from the bad pack.
Was on AO3 and was either Stiles/Derek or Stiles/Peter (most likely Sterek) *Turns out it's end game Steter
After spending 2 days digging through my AO3 history I finally found it.
It's "the earth fell away (and threatened to swallow me up)" by thosewhofall