Erm...to be honest I'm a bit surprised and disappointed with the tone of some of the replies but there are some genuinely useful suggestions for which I am grateful and which I'll follow up (if I can find them again amongst the insults, prejudice and noise). It matters to me about whether or not I'm PA so I can try to deal with it but having said that, I'm not even sure I agree with some of you about what passive aggression actually is (yep - bring it on) - surely a wide range of activities can be deployed (or witheld) in a passive aggressive way - that could be communicating or not communicating, not eating your greens, dominating the TV remote, giving someone a book (yes!), or not, and, dare I say it, being selfish in the sack. Surely it all depends on the motive? I think that's a very important point. I still think there's more to this than meets the eye.
For what its worth, I do think I have an atypical problem over conflict with my wife (I tend not to have many conflict issues with anyone else) insofar as when we argue and matters reach a certain pitch, its as if a switch goes off in my brain which gags me. It seems to be linked to a type of frustrated anger and subsides when a few days have elapsed and the issue, whatever it was, becomes more distant and obscure to allow me to calm down. The point is that I don't (yet) think the behaviour is premeditated, or part of a manipulative response. I guess I'm hoping for someone to say "yeah, some people get that, its a documented clinical phenomenon"...(which isn't PA)...