*DarthMaiden
Unlike a lot of people on MN I don't subscribe to the view that adultery always has to mean the end of the relationship.
Having said that, I can't see any other option in your case without it destroying your sense of self worth and respect.
The defining characteristic (to me) of his actions is that he deliberately shaped a lifestyle, which he coerced you into accepting and normalising, that accommodated his cheating.
This was highly manipulative and also sociopathic in its implementation and maintenance - which included not just yourself but also your mutual friend by his deliberate rejection and fabricated dislike of her - simply because she had the potential to impact his carefully prepared set up.
He clearly has no moral boundaries - yourself, your friends and even your children have all been reduced to pawns on his chessboard.
There is only one possible response to this - stop playing. Don't engage. Focus on your own welfare and that of your children.
Counselling if you feel it would help you, but certainly not with him. He's far to manipulative for that to have any possible benefit.
Tell friends, family etc what he's done. You've nothing to be ashamed of. Let him "own" what he is and how he's behaved*
^I agree with everything Darth Maiden has said above op! Your h is a dangerously manipulative sociopath! He has planned, divided and manipulated everyone around him to have his perfect life! He has no care for you, your children or even the other woman. You are his trophy wife, his perfect family for everyone to admire him for and for showing to his parents/ boss/ anyone important. He had the perfect life, a loving and naive (justifiably) wife at home looking after his children. A tramp on tap to fulfill his sexual needs whilst away from home (she is no more than a hooker to him, he has shown this by his ability to discard her with no thought for her feelings either) and a single lifestyle letting him lead his dream life whilst his loving wife raises their children alone! No wonder he manufactured the fallout with his work friend, he wouldn't want her finding out and ruining his cozy set up
You come across as so lovely in your posts op, I'm so sorry that you are hurting so much! I have a hunch that your h may be a narcissistic sociopath, look up narcissism. It would be very useful to know if he is as he may turn nasty!^