Don't go to bed angry at each other. Communicate. Problems get worse when they fester around for a few days. Inner dialogues get you more worked up than any outer dialogues will. And the outer dialogue is what usually fixes the problem.
No matter what the situation is, find a solution that works for the both of you. If fiscal separation fits, do it; if not, don't. Spending plans, where the dog pees, who vacuums the carpet, how many hours/month you can spend with the guys, child discipline; it all figures in.
Be smart. Always think things through as much as possible. Things said in the heat of the moment may not be able to be taken back.
Respect that she may handle things differently than you do. If I have a bad day, I typically would rather spend my time alone. My wife would try to hang around me and get me to talk to her about it, and it irritated me more than what happened during the day. I told her this and now she does as I ask because she understands that this is how I work things out, and respects that this is the way I deal with adversity.
Don't dictate to her, and don't let her dictate to you. Don't say, "I'm buying a Corvette, and it doesn't matter what you think." Don't let her say, "I'm buying 6 pairs of heels and a $1400 bag, and I don't care if you need to work overtime to pay for it."
I am in no way a highly religious man, but Ephesians sums it all up very well
"Submit to one another" Marriage is a two-way street. Traffic must flow both ways for it to work.
-C