My H too has said that he can't even try to work on the M because "there's too much water under the dam". He can't let go. It's a dilema, definitely.
But, don't let your H make you feel guilty about having talked to others for support during that time. I still talk to my MIL, and my H had a problem with that, but I told him that if he thought that I was going to let his voice speak for me to these people that I love and consider family, when he has shown such a lack of honor, then he better think again. Our C even told me that keeping the secret is NOT a responsibility the hurt partner has. Quite the contrary. Stepping up and facing the family and those who love the one you've hurt is part of the penance one must do to earn back his place in the family.
So, I think you can tell your H that you understand his pain, and you are sorry he feels that way, but you sure hope he can get over it because you deserve a partner who can be your partner in all facets of your life.......JMHO.
TJ
Me45,H49 D24,S18 M26,T28 Bomb 3/19/08 Sep 6/23/08 EA/PA with Secretary 2007-8 3/2009 H moved in w/OW2 7/2009 Let him go w/Love. 8/2009 Legally Sep'd