The secret for long relationships is not having a perfect and harmonious love affair. It is not how often you fight, not because of the number of similarities and the stuff you both like doing together nor the number of mistakes you made. Those things count but it is the faith that keeps you going. A relationship would last if both of you are willing to not give up, if both of you are willing to stand up and still try every time one of you or both of you fall. You should not lose hope when you are struck with problems along the way. Give each other hope and hold on as long as you can.