The Prenuptial/Premarital Agreement form is a notarized document where a couple outlines how they will handles the financial aspects of their marriage. Back in the 19th century it was a common practice. Until the prenup was signed everything a woman owned or even inherited was the property of her husband. If he died or divorced her the widow would not receive any assets or money.
Although in todays society we think of asking to sign a prenup as unromantic, it is still a common practice among most couples. These couples are looking for a way to feel secure with their financial assets. If the spouse refuses this may be a sign of bad credit or fears you may want to uncover before the marriage. Also, a prenup will protect the inheritence of the children from a previous spouse. And the most obvious, it will eliminate any debate over whats whose.
You should not look at a prenup as anticipation for divorce, it should be something you feel you need, to secure your financial assets and well-being. If you consider signing a prenup as un-romantic and a lack of trust, you are looking at it wrong, you must remeber a prenup protects both you and your spouse. I highly suggest talking about signing a prenup with your spouse early on in the relationship.