A prenuptial agreement, antenuptial agreement, or premarital agreement is a contract entered into prior to marriage, civil union or any other agreement prior to the main agreement by the people intending to marry or contract with each other. 

 A postnuptial agreement is a written agreement executed after a couple gets married, or have entered a civil union, to settle the couple's affairs and assets in the event of a separation or divorce.

Prenuptial Agreements

Premarital agreements (also called prenuptial agreements or "prenups") are a common legal step taken before marriage. A prenup establishes the property and financial rights of each spouse in the event of a divorce. So while no one is thinking about a divorce when they get married, about one half of all marriages in America end up in divorce proceedings. So it's often prudent to at least consider a prenuptial agreement. Prenups are often used to protect the assets of wealthy spouses but also can protect family businesses and serve other important functions. Learn about your state's legal requirements for a prenuptial agreement and whether it's right for you. Why Use a Prenuptial Agreement?There are several reasons why one party (or even both parties) may want to sign a valid prenuptial agreement prior to getting married. Generally, prenups protect assets that may otherwise be subject to marital property laws. Specifically, these documents may be used to:

• Protect one party from taking on the debts of the other
• Protect specified assets of one party
• Determine the manner in which property is passed on after death
• Simplify property division in the event of divorce
• Clarify financial responsibilities of the parties

The Pros and Cons of Prenuptial AgreementsEntering into a prenuptial agreement should never be taken lightly, particularly since the very mention of a prenup suggests the possibility that the marriage may end at some point. Discussion of a prenuptial agreement also can create stress in a relationship. Therefore, deciding whether to implement certain financial conditions and designations of separate property while also planning nuptials is a personal decision. It helps to understand the pros and cons of signing such an agreement.Pros

• Support your estate plan without future court involvement
• Make certain financial agreements with your spouse official
• Protect the family business and its assets
• Fewer property conflicts during a divorce
• Avoid shared debt liability

Cons

• Can create distrust and dull the relationship
• Certain elements of the prenup may already be addressed by state law
• Cannot address child support or child custody issues in a prenup
• A judge may rule parts of the prenup unenforceable, depending on the relevant facts in the case
• Non-monetary matters, such as chores and tasks, cannot be addressed in a prenup

What Makes a Prenuptial Agreement Invalid?A prenuptial agreement may be considered invalid under a number of different conditions and scenarios. First of all, a prenup must be written and signed by both parties and properly executed. Beyond that, a prenup that was signed under duress or not even read prior to signing (as part of a package of documents requesting signatures, for instance), then it may not be considered valid. Other reasons a state may not recognize a prenuptial agreement include lack of independent counsel (for each spouse), false information, and unconscionability.