A marriage agreement is only valid if it is concluded before the date of marriage. Once a couple is married, they can write a post-marriage arrangement. Even in countries that have not adopted UPAA/UPMAA such as New York, properly executed marriage contracts have the same presumption of legality as any other treaty.  It is not necessary for a couple who signs a marriage pact to keep separate lawyers to represent him as long as each party understands the agreement and signs it voluntarily with the intention of being bound by its terms. There is a strong public policy that favours parties that control and decide their own interests through contracts.  There are no state or federal laws requiring adults with contractual capacity to hire a lawyer in order to enter into a marriage contract such as a marriage contract, with the exception of a California law that requires the parties to be represented by a lawyer if spousal assistance (support) is limited by the agreement.  The marriage agreement may be challenged if it is proven that the contract was signed under duress.  Whether a pre-marriage contract was signed under duress must be justified by the facts and circumstances of this case. For example, it was found that a spouse`s assertion that she believed there would be no marriage if it was not a marriage, where the marriage was only two weeks away and marriage plans had been made, was not sufficient to demonstrate coercion.  Ito ang prenuptial agreement – o kung tawagin ay “prenup” na karaniwang “legal safeguard” sakaling may hiwalayang mangyari pagkatapos ng kasal, ayon sa abogadong si Claire Castro sa programang “Usapang de Campanilla”. “Sa lahat ng ari-arian na nakuha noong dalaga siya at noong binata siya kung walang prenuptial agreement `pag kinasal kanila na. 50-50 yon,” paliwanag ni Castro.
In the past, in England and Wales, marital agreements had not been considered legally applicable in England and Wales for public policy reasons. In California, a couple may waive their property-sharing (co-ownership) rights through a prior contract.  The agreement may limit sp assistance (although a court may set it aside in the event of a divorce if it considers the restriction to be unacceptable). The agreement can be used as a contract to make a will that requires one spouse to take care of the other in the event of death. It may also restrict inheritance law in the event of death, such as the right to inheritance allowance, the right to execution, the right to take as a predetermined heir, etc.  In California, registered national partners may also enter into a prenup. Post-marriage agreements are treated very differently in California law. Spouses have a fiduciary duty to each other, so pre-marital agreements fall into a particular category of agreements. There is a presumption that the post-parental agreement was obtained by undue influence when a party gains an advantage. Disclosure cannot be abandoned as part of a post-marriage agreement. [Citation required] Marital agreements may restrict the ownership and support rights of the parties, but also guarantee the right of one of the parties to seek or obtain assistance up to a certain limit. It may be impossible to set aside a properly designed and executed prenup.
A prenup is able to dictate not only what happens when parties divorce, but also what happens when they die. You can act as a contract to make a will and/or remove any ownership rights over the property, estate, estate, right to predetermined inheritance and the right to act as executor and administrator of the spouse`s estate.  A “Sunset” plan may be inserted into a marital agreement stipulating that the contract expires after a specified period.