@chai2,
I was thinking more of the divorce being expensive -- I guess though it would depend on which side you would end up in. The splitting of stuff and the lawyers seem to be the only that typically gets the goods. Easier I would think if you didn't get married and just kept all your stuff to yourself and split things like roommates would.
A good friend of mine commented on her divorce - said if they made it as hard to get married as it is to get divorced, I would not have ended married (and then ultimately divorced).
Also you get more tax benefits by living together than being married.