Well, because of the wealth and the setting and the fact that Cordy and Xander are married, could it be Mrs Muir's
Sanctuary? Buffy and Spike are married and Xander and Cordy are Spike's long time friends. Spike is a famous author with deep baggage in his past. One of my favorite stories.
Sanctuary by Mrs Muirhttp://dark-solace.org/elysian/viewstory.php?sid=876Summary: AU-Fantasy. William Nagle III and Alexander Harris have been best friends since the first day they met at Hyperion Preparatory School. Through the years they have always been there for each other, but one of them holds a deadly secret that will affect William's future with Buffy, the woman he loves. Will Buffy be able to hold onto the man she loves or will the secret tear them apart?