Hmmmmmm,
Yes, there is no question that at some point, you will want to ask him to forgive you, and (especially) you will need to forgive youtself. But, I'm not sure there's any point in asking him until he is ready to hear you. I'm worried that if you ask him when he isn't ready, he will just add on to his list of things that are wrong with you. I'm not 100% sure on this one, so listen for some other thoughts.

I guess if it looks like he is never going to be ready, then you just do it, maybe in a letter like MichelleLT did? She might have some interesting input here!