Marriage can be a tricky institution; you need look no further than a very high divorce rate as evidence that this is true. Therefore, if you are considering re-marriage, you may be well advised to consider a prenuptial agreement. Though it may not seem the most romantic gesture, a prenuptial agreement is simply an honest disclosure of the couple’s individual assets accompanied by their mutual agreement as to how those assets will be distributed. Nor should divorce be your only concern. Given Virginia’s “Elective Share” statute which requires the first to die to provide a one-third share of their estate to their spouse at death, a prenuptial agreement is the only legal means of ensuring that the distributions of your assets at your death mirror the provisions of your Will or Living Trust. Don’t make the mistake of thinking that you both may rely upon a mutual promise that neither of you would exercise your right of election over the other’s estate; I’ve witnessed many situations in which the survivor, either incapacitated or in need of long term care planning, is faced with no other choice but to claim an elective share in their deceased spouse’s estate. Therefore, entering a re-marriage without a prenuptial agreement may well mean that you and your new spouse have potentially invalidate each other's existing estate plan.
For example, suppose you and your new spouse each have children from a previous marriage. You intend for your house to pass to your children, but without proper planning and a prenuptial agreement in place, your new spouse could inherit your house and then pass it on to her children when she dies. Disinheriting your own children probably was not your plan.
You’ll need to follow special protocol to ensure your prenuptial agreement is valid, to include that it must be in writing, signed without pressure on either party, both spouses must read and understand the agreement, disclosures must be completely honest and the agreement cannot be grossly unfair or contain illegal provisions (such as a modification to child support obligations).
If you are already re-married and did not sign a prenuptial agreement, it may not be too late for you and your spouse to resolve these issues with a post-nuptial agreement.
Reference: ElderLawAnswers.com (June 6, 2011): Prenuptial Agreements Can Be an Estate Planning Tool.