Pre-nup wouldn't make that much of a difference in this case -- they've been married too long and Kobe has made tens/ hundreds of millions of dollars since they married. And they live in California.
If I was rich I would NEVER get married, just have different girlfriends, ala Derek Jeter. That way no one can claim my money like Kobe and Tiger. No women is worth that much cash. I apologize in advance to any ladies reading this, but no man is worth this much as either!