CV if I were you I would meet with H's counselor separately, without him there. There are undoubtedly sides to H he is unaware of or unwilling to share that the counselor would benefit from understanding. Would also be good for the counselor to know where you are in this relationship so that their suggestions and expectations for H are reasonable.

I would just offer to go in and talk to C for the purpose of helping H, not to help you, or to help the two of you. Does that make sense? I really do think that would be immensely valuable to the counselor and by extension to H.

Married 18, Together 20, Now Divorced
M: 48, W: 50, D: 18, S: 16, D: 12
Bomb Dropped (EA, D): 7/13/11
Start Reconcile: 8/15/11
Bomb Dropped (EA, D): 5/1/2014 (Divorced)
In a New Relationship: 3/2015