"any thoughts on how to let H know I find him desirable and attractive"
He already knows you do. Problem is that the A shattered his self-esteem and self-worth. Rather than going the attractive route, I would suggest you comfort him and reassure him in different ways that you aren't leaving.
He's afraid that if he falls for you again or lets his guard down, you're going to leave. There's only one way to start the road to healing in this sitch. Go to C and totally open yourself up to the C. If he refuses to go, then you go yourself.
An A and secrecy is very damaging. And an EA for a woman is the worst for a man. You made someone else top dog instead of your H.
Start opening yourself up and see if those walls start coming down.
M-43 W-40 2D - 9 and 5
Emotion, yet peace. Ignorance, yet knowledge. Passion, yet serenity. Chaos, yet harmony. Death, yet a new life.