In a marriage, there is no reason to ever have a fight. Disagreements are fine, but never a fight. Fights are nasty, mean, dirty, and hurtful. Disagreements, on the other hand, are used to work out issues and come up with a win-win solution.
Here are my tips for dealing with differences of opinion in your marriage:
Own your poop. Take responsibility for how you contributed to the problem.
Be willing to talk. Avoiding discussions because you’re “not a confrontational person” is gutless and passive aggressive. Nobody likes confrontation.
Attack the problem, not the person. Stick to the issue at hand instead of name-calling or taking digs at your spouse.
Don’t hang on to problems. If something bugs you, bring it up then and there. Don’t keep it bottled up and then spring it on your spouse later.
Provide a solution, not just a complaint. Tell your spouse what you would prefer they do differently. Then ask if that’s something they can live with.
Allow your spouse to save face. Don’t remind them of their screw-ups. At some point, we have all acted unreasonably or had bad days. Let your spouse save face (unless, of course, it’s a consistent pattern).
Make sacrifices. The best marriages are those in which two people are willing to make sacrifices for each other. You do things you don’t always want to do or like because it’s a gift to your spouse (think of the O. Henry story, The Gift of the Magi).
Now, some people are so selfish, pigheaded, or stubborn that you’re simply not going to make any headway with them. If that’s the case, you shouldn’t have married them in the first place. It takes about a year and a half to two years to really get to know somebody’s personality and character and work through problems with them so you know how they’re going to act when things go south. 
