People who live together emotionally respond to each other mostly by habit. Because the human brain does as much as possible on autopilot to conserve the scarce resource of conscious attention, specific emotions readily become associated, not only with specific events and memories but also with other emotions.
For example, the childhood experience of many adults included the following: When something happened to disappoint them, the next thing that happened made them afraid or ashamed. (We inadvertently forge this association by punishing children for mistakes.) If this emotional sequence was repeated enough, they will be prone to experience some modulated form of fear or shame whenever they feel disappointed.
Although any emotion can form habituated associations with other emotions, the most common in love relationships is the association of disappointment with fear or shame. Intimate relationships are unique in their tendency to........