Torah principles give us the wisdom and concepts that are needed for a harmonious marriage. But just knowing these ideas will not automatically guarantee a happy marriage. Torah ideas need to be internalized and practiced.
You have strengths and weaknesses, positive qualities and faults - and so does the person you marry. You have a unique life history; you came from a specific family - and so did your spouse. You have a unique genetic makeup, with a unique combination of intellect and emotions - and so does every other human being on our planet.
Your temperament, personality, communication style, and myriad other factors need to interact with the temperament, personality, and communication style of your spouse. This will inevitably create many challenges. Your response to these challenges will either create problems, pain, and quarrels... or will be the source of great spiritual and emotional elevation.
(From Rabbi Pliskin's book "Marriage" - Introduction, p.13)