Love and Marriage

How do love and marriage cohabitate? Some people would say that they don't go together at all. I believe that we have it backward and that a successful marriage is built on happiness and then marriage. Most people enjoy happiness or really pleasure and attempt to use this as a foundation for a successful marriage. There are two problems with this assumption. 1. You should be happy with the person BEFORE you marry them and 2. Your happiness is dependent upon the other person. This is a quid pro quo or this for that relationship.