Blame Game

Would someone please explain the blame game and what's behind it.  We are trying to work through things one piece at a time but I still don't get what's going through his head when he blames me for things that defy logic or reality.  It's like he re-creates history and actually believes it.  I don't understand the need for it and I don't understand if in his mind he truly believes the new improved version.  A friend's ADD daughter does the same thing and sometimes just makes her mother's jaw drop it's so incredulous.