Best Break-Up Songs?

[Ebony AKA AngieJ]

I need a really, *really* good breakup song... but danceable.  
Something slow.

My faves all seem to have the word good-bye in them.  The 
Manhattans' "Kiss and Say Goodbye" and "There's No Good in Goodbye".  
The Jackson 5's "Never Can Say Goodbye".  Teddy Pendergrass' "Send 
For Me" (which has the word "good-bye" in the chorus).  And I 
love "I'll Be There", no matter *who's* singing it.

But I can't use any of my faves in this context, darn it.  :-(

I thought about "Yesterday" (my favorite Beatles song)... but the 
sentiment's all wrong there.  I need a song that speaks to a mutual 
parting of the ways, even an amicable one.  

Any suggestions?  A standard might be nice...

--Ebony