All married people struggle with disputes that arise in a long-term committed relationship. What to do about the predictable and ever-repeating disagreements and mutual criticisms that come up from time to time, but hopefully not too often.
With your spouse, the boundaries are lowered. In marriage, sometimes, people act at their worst -- because they can with that one person. Spouses tend to let everything hang out. That causes a lot of problems and can even lead to divorce.