I'm so sorry you are struggling with all of this sadness. I don't know as I have much of anything to offer in the way of advice. You wrote you desperately want your ex to understand how you tried, but you're pretty sure you shouldn't bother. I have to say that, given the way your ex ended your marriage, I'm not sure he's really worth the bother. But if it would make you feel better to tell him, I'd say go for it. It may well not change anything. (Perhaps it's for the best if it doesn't?) But perhaps it may cause him to consider what he did. He should...

Here's a link to an article, from Psych Central's archives, on how to awaken your soul following heartbreak:

How to Awaken Your Soul After a Broken Heart

My best wishes to you...