So many people pretend to each other that their relationships are going well when they really aren't. They don't dare to talk about the problems let alone find resources to help solve those problems.
They may believe the myths that kill relationships and try to hold themselves accountable. "Don't argue" is one of the myths. It assumes you agree with each other, but it really means that one or both of you is giving up what you want in order to try to please the other. Since you don't really know what the other wants, you may or may not be successful at pleasing your partner.
Your resentment builds under the surface. You barely know it – you're so focused on your partner's needs instead of your own. You attribute your headaches or indigestion to stress. You smoke or use alcohol or drugs to manage the stress, and one day you decide it's all your partner's fault, that you've fallen out of love and need a new partner. Then, you tell your partner, who still loves you and begs you to go to counseling together.
And it's all because you believe the "Don't argue" myth. Of course, if argue means shouting at each other, calling each other names or throwing things, I can see your point.
But if arguing means having a verbal disagreement where each of you says what you want and explains your point to the other, then you're missing out. This kind of arguing only works if you are each willing to listen to the other without interrupting or justifying your own position.
In my office, most of my work with couples is about teaching them to express themselves and listen to their partners. Once they do this, they're ready to repair the respectful basis of the relationship and build a new one based on mutual respect and caring instead of mythology.
If you enjoyed this article, Being Happy Together: How to Have a Fabulous Relationship With Your Life Partner in Less Than an Hour a Week will provide you with much more information that I believe will be useful to you.