That's hard, Cailin. You are so strong, but I agree about the acceptance thing; we are a lot more "sane", when we can stop and think, " I'm the grown up here".
There wouldn't be any point in sending my Mum one of those, "Why Does He Do That?" books at this stage, would there? The simple answer to that question is because he's an appalling shit and he has been allowed to be.
My poor mother had a violent father, her mother died young, so she was left with him until she ran straight into the arms of dad. She would always say, "oh, if he ever lifted a finger to me, like my father, I'd be off". So with those words, she gave him carte Blanche to do everything but; nasty out bursts of temper, sulking, occasional pissed of of his skull drinking. That's all fine; he's great 90% of the time (hilarious, generous, sentimental, just lovely) but its ok to be scary and frighten her as it isn't physical.
I voiced all this a couple of years ago when he was being a shit and I said to mum in front of him, "you know this is abusive. Just because he isn't hitting you, doesn't mean it isn't abuse." He was going mad telling me to shut up and I carried on calmly saying I wouldn't shut up. Mum actually showed a bit of spark then and said she had a mouth of her own. She told him he was a big bully. He phoned to apologise and took mum on a weekend away, bought her some nice things - and so it continues. Except this time it's not ok.