Two words. Duct tape. Comes in many different colors now, and you can probably change it out according to what he's wearing for the day.

Just kidding, of course.
I had a similar marriage and learned to stop defending myself. It seemed to make matters worse. He would dismiss me, not want to hear me out.
My advice is to walk away. I know you said you've tried that, but you have to be consistent. He has to learn that he won't have your attention when he starts yelling.
He also needs to know at the onset that what he's saying - either his tone or WHAT he's saying is hurting you. It doesn't have to be a big long explanation, just "Ouch." or "That hurts."
So typical scenario:
Him: "Don't you ever use your head? I told you to mail that *&^%^& bill, and you didn't do it."
You: "Wow. That really hurts. I can't stand here and listen when you're like this. I'm going to clean the bedroom. When you're feeling better, maybe we can talk about it in a civil manner."
Him: Follows you to the bedroom and starts in again.
You: "I'd love to talk to you about it. When you can talk to me in a normal, nonabusive tone, I'll be willing to listen. Until then, I have a ton of things to do." Then you leave and go to another room to clean or do something else.
If you have to, take a walk outside, or go run an errand.
Now...here's the thing...when he IS civil, he needs to be rewarded. You need to:
[list]
[*]Maintain eye contact
[*]Not interrupt
[*]Listen attentively, nod, and give short answers to keep him talking.
[*]Mirror what he has said e.g. "So, what you're saying is the bill was already late and now I made the situation worse..(fill in the blank.)" This makes him sure that you heard him.
[*]Validate what he said. "You're upset because I forgot this and it was important to you. I'll send it out tomorrow. In fact, I'll put it right on top of my coffee mug so I don't forget."
The idea is to NOT give him any attention when he's being an a$$. If you do, then that's telling him that he can be an a$$ and it has no consequences. It's like giving candy to a 6-year-old just because they're crying. You don't know WHY they're crying until they calm down and explain why.