Bube, The fact that D19 wouldn't intervene while her sister was getting hit with a dog leash says volumes about what they think of your wife.
I know she's not ugly all of the time but she obviously does it enough that they are afraid of her on bad days and only dread her on good days. Although they might not be in imminent physical danger, the mental relief they'd feel at having her out of the house would be worth it, don't you think?
It bothers me to think of how she treats you within your marital relationship but it sickens me to think of how she has made your daughters feel over the years--second to animals, dreading the next outburst, the guilt-heaping and pity parties and general narcissism.
I think you're doing great, Bube. The changes you've made in the last week will propel you on to solidifying those boundaries. I wish you well.