What's the point?

Why do celebrities get married? I mean seriously, how many celebrity couples make it? Take for instance Rene Zellwegger and Kenny Chesney. They were married in May of 2005 or 2006, and when I heard the news, I instantly said "I give it 6 months". It lasted 4. By September, they called it quits. Why do any of them bother to go through the whole process? None of them are going in to it for the marriage, they only want the wedding. The same could be said for us "normal" folks, but it's mostly true for the celebrities. And how many times does Liz Taylor have to be married? She's making a mockery out of it. And Charlie Sheen? If some of these people would put the same amount of time into a project or charity that actually meant something, they might do a little good. Oh well...