If you've got the courage to do it, here is a potent line for you to use:
"H, I'm sorry I've been such a biotch lately."
Follow it up with:
"Sometimes I get too caught up in my own hurt to pay attention to yours. I'm glad that you don't want to lie anymore. Neither do I. Can you help me understand your pain? I really want to understand it. I promise to listen and not judge you. I want to see how I can improve me so I can improve us."
That should open up the floodgates. Be prepared for a laundry list. Do not judge him. Do not react. Just listen and take notes. When he is done ask him which is the most important pain and what you can do to relieve it.
Take the first steps. I won't be surprised if he starts to reciprocate soon.
