Two of my close friends just had babies and I passed onto them a golden rule of parenting that was given to me when we first had Jenna...
Do not talk to your spouse between the hours of midnight and 5 am when caring for your baby. Nothing good will come of it.
This may sound silly...but honestly at 2 am when you have a crying baby are you really going to say anything nice? When your kid is teething at 3 in the morning and you're so freaking tired you can't see straight, what productive conversation could you possibly have? I don't know about the rest of you but those middle of the night wakeups make me frustrated, tired and not a happy camper. Not exactly a good state of mind to start talking about things.
When I first got this advice, I thought it was silly - we were still in the "we take care of our infant together in the middle of the night" phase. Then we realized that's it's dumb for both of us to be up and we should take turns (which we still do now) and inevitably the one who's up is not happy with the one who's still sleeping...hence the no talking rule.
We're usually pretty good about sticking to it and when one of us forgets the other reminds them. Like last night, Jenna woke up from the crazy rain, I went in and got her back to sleep and when I came back to bed, I tried to have a whole conversation with Mike about the weather and I think I even tried to discuss some current events...his response? "Honey, what are you doing? We don't talk now." Right - those are the rules!