I know Peter that it's really hard to not bring things up that bother you, but you have to fight the urge. Go for a walk, journal, post here, call a friend but do what you have to in order to keep it out of the discussion.
I used to work with at-risk youth. One of the things we worked hard on with them was what we called "the one second". They all had high-running emotions and would react to everything all the time. They couldn't control their lives because they were constantly reacting, reacting, reacting. Someone would say something and immediately they'd respond. Which would garner a response to which they'd respond, and before you know it a fistfight breaks out. Sound familiar (except for the fistfight)?
We worked hard to have them give us just one second. One second before they opened their mouths, one second to process what had just been said. Just try it... say "one one thousand" out loud and see how long that really is. It certainly gives your logical brain time to catch up with your emotional one.
I've had to work on that myself. For me right now it's that my wife doesn't wear her wedding rings (especially when she complaints that an icky, 65 year old doctor at work is hitting on her... gee... I wonder if there might be a solution to that?). At least four times a day I feel this incredible urge to ask her about them. And each time in my head (and even out loud once in a while) I say "one one thousand". And then my logic brain catches up and reminds me all the not good things that question could generate, versus only looking at the temperature taking that my emotion brain so desperately wants to make happen.
Married 6 together 8 Me:38 W:31 second marriage for both SS12, SD10, S6 Bomb: 9/8/11 (day before our 5 yr ann) W moved out: 2/18/12 D final: 11/12/12 Share S 50/50. Spend as much time as I can with SS & SD