Prenuptial agreements are often fairly easy to enforce because they occur before the marriage. However, a postnuptial agreement may not be as easy to enforce because it occurs after the marriage. It is essential if you want to create one that you understand what it needs to make it valid and what things will automatically invalidate it.
According to the Colorado General Assembly, there are a few key details that could invalidate your prenuptial agreement. You both must sign the agreement of your own free will. If one of you does not sign it, then it is not enforceable. If there was any duress or someone forced you to sign it, then it is invalid.
Before you sign the agreement, you and your spouse both must have the chance for legal representation. If one of you does not secure representation, then a waiver must be in the agreement that states by signing it, you could lose some rights, such as the right to property, or take on some obligations, such as the responsibility to pay off marital debts.
You both must honestly and completely disclose your assets and finances to the other person. You must know the fair market value of all assets or it is reasonable that you would know that. Not including an asset or failing to provide full information could invalidate the agreement.
Your agreement cannot limit child support or set up custody arrangements. It cannot break the law or go against a court order. It also cannot penalize either of you if you should file for divorce or separation.