I'm gonna have to go with Qliveur. It doesn't make your life better or easier. There's just soemthing about being legally bound to a person, no matter how much you love them, that detracts from the relationship and puts it under strain. Do you know how much you can fall out of love and learn to despise someone by thinking of them as a legal obligation instead of a relationship built on trust and commitment that doesn't need a paper saying you love one another?
The benefits do not outweigh the setbacks. Don't get married.