Today, my emotions have been up and down but I am calming myself down for the night ahead. I am not pissed off but more like "whatever", bring what you want I can handle it. But putting this into action is always harder than I think. I know exactly what you are saying here. In my opinion, this is where the fight for your marriage is won and lost. The good intentions - I had this too. And d4mn you are right about how hard it is to put into action. But this is where success is determined.
I don't have any secret weapons for you, for maintaining control of your emotions. Just lots of encouragement. Do whatever it takes. Meditate. Read books. See a guru. Workout to exhaustion. Take drugs. Get creative. Whatever it takes to stay cool.