Failure To Observe The Requisite Formalities

• Separation agreement law is different in every state; if your agreement doesn't comply with the terms of your state's laws as to execution and acknowledgment, your agreement could be held invalid. In North Carolina, for example, all written agreements between husband and wife must be notarized; an otherwise valid separation agreement would therefore fail just because you neglected to have your signature notarized. Depending upon the facts of your case, your spouse could then assert his claims against your estate even though you were separated at the time of your death. In such a case, you wouldn't find out your separation agreement was no good until it was too late to do anything about it.
  
  

Failure To Include The Right Language

• In some jurisdictions, the circumstances of your separation may be sufficient to protect your estate even if you never signed an agreement; unfortunately, by the time this becomes an issue for your estate, its best witness -- you -- will be dead. Just having a separation agreement, though, won't be enough to avoid this problem. Your separation agreement should contain an estate waiver clause specifically stating that each of you waives all claims you might have against the other's estate.
  
  

Fraud and Misrepresentation

• The presence of fraud or misrepresentation in the negotiation or execution of your separation agreement may result in its being held invalid. Your ex might claim she was duped into signing the agreement upon the mistaken belief that only certain assets or debts existed or that you earned less money than you actually did. While you may have done or said nothing wrong, your estate stands at a marked disadvantage because you won't be around to tell your side of the story. To avoid this problem, make sure you make a full disclosure of all your assets and that you include a disclosure provision in your agreement.
  
  

Duress And Coercion

• Coercive behavior sufficient to invalidate a separation agreement includes acts of or threats of domestic violence, blackmail or blocking access to your children unless your ex signs it. Although you may have done none of these things, your ex might later claim you did; as such, it is essential that the agreement be an arms-length transaction in which your ex has plenty of opportunity to review the agreement with a lawyer before he signs it. Claims that someone only signed a document because he was scared or acting under duress can evaporate when that person had ample opportunity to tell his lawyer.