Most of the time, married couples should be in agreement. Especially when it comes to big things like your relationship, your family, your beliefs. But when a minor issue has the potential to become a major problem, then it's better to keep the peace than to be right. For example, if my wife and I are buying a couch and she picks one that I don't really like, I can dig my heels in and fight, or we can try to preserve the peace. For her, it was important…for me, no big deal. Even when you agree to disagree, you'll need to protect your relationship during conflict. But some things are non-negotiable. Here are 11 things a husband and wife must agree on.