So it sounded like he's willing to keep working on it if you two have a tool in place to make him feel like he will never experience another long or loud conversation? Well, who cares who he blames it on if he is willing to actually try a new method? This is good news, right? Then end goal is the conflict will be reduced and then he'll stop bringing up the past, right?
Maybe if he gets to feel "in control" he will be willing to try and relax and reduce his number of blow-ups over the computer and the like in the future.
