MC treats the M, and your M didn't fail. Your H did. Your M doesn't need to change. Your H does.
He knows he cheated to get external validation. That's almost definitely true, and it's almost definitely a good start. I just don't see how communicating better in your M will help him fill that metaphorical hole inside him. MC can't fulfill the need for external validation - that's his own work.
I've loved my W since 1965. She never loved herself, so she simply did not take in my love. She refused to recognize she was loved. She rarely let herself feel loved. I was proud of her from 1965 into her A in 2010. My compliments never filled up the hole inside her, either. If you read enough here, you'll see that's common - or at least not uncommon - for WSes.
Your H will not be a good candidate for R unless he learns to love and validate himself. The hole is too big for anything you say or do to fill it. The hole is inside him, and he's the only one who can fill it.
To heal - to change from cheater to good partner - your H has to face himself, his pain, and his fears about himself, and he has to face them down.
The counselor has us talk about our communication style and help us realize what led up to the affair.
There's nothing you could have said or done to prevent your H's A.
It's great that he's interested in doing IC. I urge you to require a couple of things from his therapy. First, one of his goal needs to be something like 'to change from cheater to good partner.' A second goal should be something like, 'to learn to love and validate myself'; religious doctrine may help.
Third, my strong reco - to all BSes, though I don't write it out much - is that you require him to sign a release that allows his IC to talk with you about your H's goals and progress. (My W's IC suggested that I require her (the IC) to call me proactively if my W revealed another A or if she rescinded the release.) IC is ethically and legally - usually - confidential, and an IC can't communicate about anything that goes on in IC, except for a few exceptions relating to violence, to someone other than the client without a signed release.
*****
My reco is to forget about forgiveness having any connection with R. Your H has hurt you very deeply; forgiveness needs to be earned, IMO. Besides, you can R without forgiving. You can forgive and D. We BSes deal with very basic and raw emotions, and there's no one size fits all.
Those words you can't take back? You decide how you are going to interpret them. There are numerous healthy ways to do that. You get to, and must, decide for yourself which way you'll go. If you're not sure how you want to take them now, rest easy - you'll almost definitely figure it out, but you're not ready yet - and that's not unusual or abnormal.