And I interrupt a lot when I see where the sentence is going, i.e. "you've been irrational, spontaneous..." Interrupt "what are you talking about?" That kind of stuff. Am I truly supposed to validate that BS????
You can validate his perception.
Look at what the choices get you. If you disagree, he'll step up his offensive. If you agree, it helps to take the wind out of his sails. But just agreeing isn't all you can do.
"You've been irrational" is his perception. You don't believe you've acted irrationally. So his perception can be validated with something like "Well, I may not seem to be acting rationally to you all the time", but then I'd ask for an example: "Can you tell me of an instance where you think I was irrational?" Then have him explain why it seemed irrational to him. He'll give you his perception of it, which you then can examine and see where it differs from your perception of it.
