Spike and Dru have an open-relationship

I read this somewhere before and I can't remember where, who it's by or what it's called. All I remember is that Spike and Dru have an open relationship and hire Buffy as their babysitter for their son. Buffy moves in with them while babysitting but eventually falls for Spike and I can't remember the rest.. if someone could help me that'd be awesome - thanks!!

I think it's That Hole in Your Life by BTVSLOVER82. It's an indefinite WIP but if you go to her livejournal, there's a summary of the rest.

Thanks a lot for the info!

Thank you! I've wondered forever what that story was and where I lost it. I loved it, it was so well done. Sad that it hasn't been updated, but at least now I know where I put it.