Fear is natural. Defensiveness naturally accompanies fear. Skillful partnering requires practicing techniques that allow me to drop the defensiveness despite my fear. When I deny my responsibilty for my part of the issue, I wind up blaming my partner and trying to change him or her. Remembering mainly the negative experiences in a partnership is a predictor for future breakdown.
All partnerships have their difficult spots.
Partners that stay together are proud of their ability to weather the stormy seas and are warmed by their memories of the happy times spent on tropical beaches. Refuse to get help. Believe that changing partners is the solution. People may go through several partners while repeatedly avoiding the same basic issues. We naturally choose partners that push our buttons for our personal development.