Hi nodoover,
For years I was real good about walking patiently away when he would start a rage or angry tirade but now I feel weak and a lot of the things he attacks me with are true so its hard for me to leave. I have said a few times you are right, I am upset now and did that but it doesn't mean I have to listen to you rage.
he knows you well so he knows what words to choose to maximize impact. PwBPD are masters in invalidating others
Often the way this game works is that the pwBPD chooses stuff for emotional impact. When it is untrue one may be disputing the facts (and have a fight over them). When the stuff is true but still hurts what to do?
a) you are feeling hurt and you have every right to protect yourself in a peaceful manner. Boundaries are not fighting tools but are means for self protection. You feel for whatever reason that you need space - take it!
b) step of the logical level and go down to the emotional level. Imagine a communication consisting of two levels - one logical/fact oriented - one emotional/feeling oriented. Just because he e.g. starts talking finances to evoke guilt you don't have to respond with financial facts but e.g. validate feeling stressed about money or even further away validate that life is hard for him. Voicing emotions thrown at us is often a good way to disarm them, getting less hurt and throwing them back is often a good way to decrease them at the origin.