At last David realized that Saul would eventually destroy him, so David fled. So David turned disloyal? No, David twice refused to kill Saul in delf-defense, and Ahimelech the priest told Saul that David was Saul's most loyal servant. Yes, David's ministry suffered. He fought against less enemies than he had before, and when Saul needed him the most, David wasn't there to prevent a massacre of Israel's army. But David went on to become a great king just the same.
The point? Sometimes, the best way to deal with jealous leadership is to leave peacefully.