Have you noticed that you and your partner keep having the same fight, over and over again? The SUBJECT of the argument might change -- something she SAID, something he DID, something someone did NOT say or do -- but the struggle remains the same. One of us get angry and attacking, the other one gets withdrawn and rejecting.
Under enough pressure, sometimes we BOTH get heavily into a mode of attack-and-defend and defend-by-attacking each other. Before you know it, the person that you know and love and have chosen ABOVE ALL OTHERS to be your one special partner feels like your very worst enemy.
That is a common occurrence for a married couple. Not everybody experiences it, and those that do are not having that experience all the time, BUT it is a common enough pattern that there are therapy models designed to address that very thing. That pattern of behavior in couples has been called "The CYCLE" by many. Below is one person's conceptualization of that interactive cycle. Emotionally Focused Therapy uses this kind of theory to help couples.