The backstory is long (and sort of boring) so I won't go into it here, but through a winding series of events I ended up contacting a friend from where we used to live.  (Side note: she might have been the only friend I actually made while we lived there.)  She begins to tell me of how her husband had cheated and that I'd never guess who his affair partner was.
No... not my husband's affair partner, but darned close.  One of her besties who works in the same office with her.
My friend joked (she can do that now that it's 2 years past DDAY and her divorce is finalized) that there must be something nasty in the water over at that office.
She also alluded to the fact that "everyone" knew everything about my whole situation, which, of course, means that no one really knows anything except rumors and speculation.  I'm SO freaking glad we moved 3 hours away and I don't have to deal with that crap anymore.
I am regretful that I didn't stir the pot more when it came to calling attention to the affair.  Most companies have policies in place to deal with this, but not my husband's work or the OW's work.  (Different offices but they work together.)  It's stupid - and clearly - needs to be addressed.  Obviously, even if I had stirred things up and even on the chance I had caused enough of a ruckus to get policies put in place, there's no guarantee that my friend's husband wouldn't have cheated on her, but I feel like at least there would have been consequences which made it less of a pain for her to have to spend so long and work so hard fighting for her rights in court during a long, messy divorce.
Bah.  Woulda coulda shoulda.  She's doing well, now, and so am I.  In the end, this is what matters. 
That said, someone really should go pour some bleach (a LOT of it) in the water jugs over at that office.  (And the bitter part of me says: or cyanide - but you know, that's petty so we'll ignore it.)