I offered this description to an earlier poster's request and it's not the right fic, but I don't remember the title or author of this one I read but maybe someone will recognize it.
There's a "time travel but not really" element to this story wherein Justin is having really bad dreams and somehow, with the help of, I think, a vintage bookstore owner and Mysterious Marilyn, they figure out that Justin's dreaming of his and Brian's past in England and maybe in other lifetimes, too. Brian's someone in authority and Justin's an indentured servant or something. Mikey's involved, too, in a negative way. Anyway, they have to resolve whatever was left unresolved or there will be a bad result in current time.
I don't remember exactly, but somehow the bookstore owner's past is also entwined or his lover's past, something; maybe one of their relatives turns out to be a relative of Brian or Justin. They all go to an old burial area in this one at the end of the fic to kinda lay the past to rest.
I didn't expect to enjoy this fic as it's a little AU for me, but I did. And now I'd like to read it again if anyone can help me find it.
ETA: Found quickly, thanks to
charlie_jae and
rusty1982. Herewith,
Eternal Triangle