If you graduate from college or high school, you get a piece of paper that represents A LOT. It sets you apart. It doesn't mean that you're any smarter than somebody that didn't go to school.. Also, People can drive without a driving license but if you don't have a license, you don't have the RIGHT or privilege to drive. The same with marriage. You can be in love but you don't have the right to certain things when you are not married legally. Marriage is a legal bind that puts you in a union with this other person. It's a partnership. It legally protects you and your relationship and gives you rights that other couples don't have. If marriage was just a piece of paper, couples can just rip it up and marriage would be over. Why do you think gay couples fought to be married if it was only about love and a piece of paper.
To me marriage is not JUST a piece of paper nor is marriage just about love. Marriage means someone loves and trust you enough to go into a lifetime partnership with you. love and trust you enough to commit their life to you. They trust you with their life, assets, money, and children So if anything were to ever happen, legally the spouse is the one that has the say. Not the state. Not the family. That's why a witness is needed.