S, I know exactly how you feel. I really do. I have felt it deep into my soul. I ached for him. Even when he did the unthinkable. I found compassion because of the love. I found it because I believed in the man I once knew.
Even though we cannot know what it feels like to lose a child unless we have, we can still find compassion and empathy.
I do not blame you for wanting to understand. It does help fuel the positive feelings. As long as you know you cannot possibly understand it completely.
Sometimes we can get stuck in the wanting...and it gets in the way of our journey.
Your old marriage is gone. Tuck the memories safely away. But that doesnt mean a new marriage, built from weathering the toughest of storms, isnt possible. That one will be built on a new kind of strength and depth.
I hope he finds his way back to you, my friend, because you are amazing.