Love is not only a feeling, but an action. If you love another person you must treat them with love and respect, in order to fuel the fire. The sort of love you have for a friend is different from the love you feel for someone that is more than just a friend... A friend can stab you in the back, turn around and laugh it off with you... but because spousal love is so much deeper than the love of a friend, if your spouse stabbed you in the back, even once, it would be much more difficult to forgive.