Marriage works for some people, not for others. Big deal.
I like the idea that at a certain point you can give your significant other and yourself mutual legal benefits from the government, but I don't believe that this should be the end all and be all for relationships.
Personally, I'm not planning that far ahead in the future, but I'm open to the idea.
Should probably add that my parents divorced when I was 3, both remarried and divorced again, my mom's been married for about 10 years and my dad's single. I would have rathered my parents stayed together, going back and forth is not exactly fun, but I understand their decision.