If you are going to respond to him at all, make it about yourself for a change.
Turn the tables - ask him to walk in your shoes for an hour - Moser in a previous post made a very good point!
Ask him - how he would feel, if he suddenly found out after all these years you had had sex with another man just before your wedding and everyone knew about it, but that's all OK now as you had decided it was better to keep yor Husband in the dark, even though everyone else knew about it all along - even your own family.
Add to the fact - as time went by - you decided to introduce your "close friend" - that you were now still working into your family and encourage a close friendship with your husband.
Then when "your close friend" gets married you're there at the wedding -snivelling away and writing volumes of utter shit to your DH about how you just don't know how your feel - but don't worry I never meant to hurt you.
Ask him how would he feel - would he feel humiliated, angry, foolish, whole life was a lie? laughed at by everyone?
One last thing, the fact that he knew all of your friends knew and still said nothing to you is something I don't think I could forgive.
In addition to all of this - your Husband might not have an option as to whether or not he can still be friends with her, or her with him. Remember she has a new husband now. He will not want her anywhere near him.( unless of course he's as fucked up as them too!).
You will be alright OP. but give yourself time!