Wolf, the advice on this page from Steve, LH, R2C and IH is golden. Read it and really take it to heart.
The fighting has got to stop, that would be a huge 180. Listen and validate, that's it. Nothing more. If she says "Wolf, you are single-handedly responsible for the decline of civilization and you are why a meteorite struck the earth and killed the dinosaurs and you are also why I was unhappy when I opened my Christmas presents in the 3rd grade and didn't get the Happy Donna Doll I asked for" then your response should be "that must have been difficult for you, it sounds like you are sad and frustrated, is that how you feel?" Just listen and validate no matter how outrageous her claims seem to be. Because anything else will just to a fight, because right now she's programmed herself to escalate.
Recognize and identify what you're doing wrong and stop yourself before repeating it. It is very VERY difficult to do this, but do it you must. Years ago someone that posted here used to say that when he was interacting with his W he would picture me on his shoulder telling him what to say and do and what not to. Sure that was flattering to hear, but more than that it's a BRILLIANT technique. I'm not saying picture me in particular, but just try to imagine the vets here collectively perched on your shoulder coaching you when you are around W. Maybe that will help you break out of the cycle.