Hi!
There has been one fic I have been looking for which was an All human fic, where Buffy was married to someone else, who is dead when the story begins. Spike is an old friend of theirs and has been in love with Buffy all this time (a fact know to the husband whos name I can't remember). Buffy has a child who she thinks is her husbands, but is actually Spikes (had something to do with artificial insamination).

As the fic goes on, Buffy and Spike start going out together and finally Buffy finds out (through a letter, maybe?) that the child is actually Spikes and that he has always been in love with her.

Does this ring any bells with anyone?

Her Shoulder To Lean On by Katkin

I have a copy on my computer, so shot me a email though SR.

That's the one? I was looking through my likely fics and realized I just didn't really know so gave up, but that was one that was a strong possible. Good to know. I'm going to add the OP description to the summary I already have so I'll remember it was this one. Thanks for finding it.