Okay, I hope you don't think I'm crazy when I describe the little bit I recall of this fic

I swear I read it, but no searching can lead me to find it!
I'm remembering one specific chapter where Spike was called out for a (security system?) job and the clients were Michael (Douglas) and Catherine (Zeta-Jones). Buffy went with him (they may have been staying one the pool/guest house) and at one point they were swimming in the pool with Catherine. Also, Buffy may have been pregnant.
Any clues as to what this fic is?!? Please! It's been driving me nuts!