Why was Martha upset by her husband's decision to become President as noted in the biography, Washington: A Life?

Martha was close to her husband and during the eight years during which he led the Continental Army, Martha would often take the long, hard trips to be with him and his army. Martha's presence would often boost the morale of the troops. Later, when Washington finally came home to Mount Vernon, Martha was content to have him there. Therefore, when Washington made the decision to become president, Martha was unhappy with his choice. However, Martha followed him to New York and fulfilled her duties as first lady.