May,
I read all of this like 3 times.

1. find a new IC that is marriage positive (Mine has been a huge help in me navigating the reconciliation and the early days of piecing when any mood change or tiff would make me cry because I felt like he was counting points against me. That was all me not him, he was in but I spent so much time being weighed against OW I couldn't let that pageant contest feeling go. She also helped me a lot with communicating and articulating my anger and sadness without "attacking" or seeming like I was doing so). The amount of anger and resentment you have can't be washed away but you sincerely wanting MR 2.0 but living in and holding on to MR 1.0 is a contradictory thought process and you need someone to guide you through this if you can't see yourself getting there on your own any time soon.

2.Do the ceremony do what ever you need to do to make your brain realize this is a new relationship this is a fresh start. His job is to let OW go without regret. He's done that. You're job is to let your anger go. You haven't. It's always been that way. You know how much I care about you, but these unrealistic expectations for him to hate OW or be disgusted by her is in all honesty, an immature requisite. If he's disgusted with himself. He's reached true remorse. You can't ask for more than that. It's unfair regardless of how awful and gross he had been. You can't hinge your forgiveness on unrealistic expectations. You can't hinge your forgiveness on him at all. It's not about him. It's about you.

3. Him wanting to resolve this through MC on his own fruition is one of the steps of R and piecing all the vets talk about. H is doing his work. What step in R and piecing do you think you can take to get one step closer to H on that bridge of piecing? Maybe baby steps, much like H took in the beginning here is what you need to move toward forgiveness. What baby step can you do? Maybe a viewing of What About Bob to take those baby step with a spoonful of sugar instead of swallowing that bitter pill dry?

Good luck, my dear. You got this. XOXOXO