You may have heard the case of Elizabeth Petrakis, the woman who got her prenup thrown out.
Here is the full story as a reminder: http://abcnews.go.com/blogs/headlines/2013/04/n-y-prenup-battle-winner-destroyed-family-with-affair-cousin-says/
This woman meets a successful millionaire who's built his own fortune through his life's own hard work and investments in real estate.
She wants to marry, being a smart guy he naturally is wary that she could be after his money. She doesn't want to sign a prenup, but he says there is no way they are getting married with out one, so she reluctantly agrees.
Well, come several kids later, she hits the wall and wants a divorce. She claims the prenup is the reason for their marriage falling apart, even though she never was forced into it. She could have always refused the marriage and refused the prenup. But those were his conditions and she accepted it.
Well it turns out she was full of shit. She was cheating on her husband with her cousin's husband. When her cousin comes out against her with this, she has no option but to admit to it. But she still insists her affair wasn't the reason for the marriage falling apart, oh no, she still insists it was the pre-nup.
Here's the real kicker:
She tells the judge that her husband had promised her he would get rid of the prenup after they had children. That's what she says, that he made an oral agreement with her. She has no proof of this promise or this oral agreement, its just his word against hers.
Well the judge believes her, and throws out the prenup, and now she is entitled to half his money, even after she cheated on him, even after he thought he was safe by signing a prenup.
Remember guys, not even a prenuptial agreement can protect you. Marriage can and will destroy you, there is absolutely no point.
Be careful in even entering a de facto marriage before you live. In some countries, being in a LTR with someone where you move in together and live together for some time as de factos can still grant the ex-partner your assets should you break up.