In most cases, divorces are not prompted by a single concrete moment of conflict or a dramatic affair. The death of your relationship is the result of a million tiny paper cuts that eventually create an accumulation of wounds so severe there is no healing them. As soon as mutual respect is lost in a relationship, so are any hopes of putting things back together.
While it may seem like the best approach to keeping the peace and maintaining happiness in your marriage is to avoid all conflict, it turns out that being non-confrontational is not actually helping you in the long run. Rather than avoiding all confrontation, it is much better to pick your battles. This doesn't mean you should shine a spotlight on every little thing your partner does to annoy you but instead think about whether there is a common theme or root cause that could be addressed via a mature and respectful moment of respectful confrontation. When you fail to address underlying problems in your relationship, it is natural for resentment to build.
Holding on to resentment is one of the easiest ways to relinquish control of your own emotions to another person. There is absolutely no benefit or redeeming quality to resentment and in the long run the person holding onto it will most likely suffer the worst.