I don't think you're going to figure him out.
I had to work on my family of origin problems, my own patterns so this doesn't happen again. In the past I tried to jump in without really getting to know someone first. I desperately wanted to be loved since I didn't have a present father (divorce) and my mother was super detached to the point of being completely checked out. "Daddy issues" are common with codependent women, but non-availability (emotionally) is practically an epidemic with men.
None of us can get in someone else's head. I would say focus on you. Every relationship ends with a million questions that will never get answered, and I found that examining my own patterns was the only way through.
I could not then and cannot now control someone else, but I can slow down my involvement levels and not repeat my same mistakes. I can go into things with men VERY slowly, and I do. Much less hurt that way.