I know I am incredibly cynical but there is nothing positive about marriage, only negatives.
A marriage brings nothing new to a relationship, I know people have stated that it is a sign of commitment to their partner & there are plenty of long, happy marriages out there. These are relationships that would last regardless of marriage. You don't need a ceremony or a piece of paper to show your feelings towards your partner, if it's right, it's right. However if a relationship isn't quite right from the start or deteriorates over time then that piece of paper opens a world of hassle & grief & prolongs the pain of separation. Let's be honest, relationships fail, a marriage certificate only complicates this. It becomes a matter of law instead of the heart.
Two people do not need a certificate or ceremony as proof of their feelings, how they are with each other each day is what counts. Not a piece of paper & a fancy ceremony.