As more and more people marry more than once, prenuptial agreements have become an important estate planning tool. Without a prenuptial agreement, your new spouse may be able to invalidate your existing estate plan. Such agreements are especially helpful if you have children from a previous marriage or important heirlooms that you want to keep on your side of the family.

A prenuptial agreement can be used in a second marriage when both parties have children. For example, suppose you get remarried and both you and your spouse have children from a prior marriage. You want your house to pass to your children, but without proper planning and an agreement in place, your spouse could inherit the house and then pass the house to her children when she dies.

It is important to make sure your prenuptial agreement is valid. Following are the major factors needed to ensure this:

• In writing. To be valid, a prenuptial agreement must be in writing and signed by both spouses. A court will not enforce a verbal agreement.
• No pressure. A prenuptial agreement will be invalid if one spouse is pressured into signing it by the other spouse.
• Reading. Both spouses must read and understand the agreement. If a stack of papers is put in front of one spouse and he or she is asked to sign quickly without reading, the agreement can be invalidated. The spouse must be given time to read the document and consider it before signing it.
• Truthful. Both spouses must fully disclose assets and liabilities. If either spouse lies or omits information about his or her finances, the agreement can be invalidated.
• No invalid provisions. While the spouses can agree to most financial arrangements, a prenuptial agreement that modifies child support obligations is illegal. If an agreement contains an invalid provision, the court can either throw out the entire agreement or strike the invalid provision. Similarly, if the terms of the agreement are grossly unfair to one spouse, the agreement may be invalid.
• Independent counsel. Some states require spouses to seek advice from separate attorneys before signing a prenuptial agreement. Regardless of whether it is required by state law, it is the best way to make sure each spouse's interest is protected.

Though a prenuptial agreement is an agreement that is signed before marriage, sometimes similar agreements can be made after the wedding (called a post-nuptial agreement). To find out if a pre- or post-nuptial agreement is right for you, contact your attorney.