In the past, in England and Wales, marital agreements had not been considered legally applicable in England and Wales for public policy reasons. What the matrimonial regime cannot cover is something illegal. Nor can The Prenup have a provision contrary to public policy. For example, future child care rights cannot be agreed in the agreement. States consider the welfare of children to be a matter of public policy that must be decided by a court when a marriage ends. Nevertheless, a post-up can be beneficial. If you didn`t think you needed a prenup or didn`t decide not to create one, postnup is still an option. Their comfort level, which speaks of marriage and money, may have changed. Or the choice that a parent stays at home to raise children may lead you to reconsider this type of agreement. A sunset arrangement can be inserted into a marriage agreement stipulating that the contract expires after a specified period. In Maine, it automatically expires after the birth of a child, provided the parties do not renew the contract if the parties do not renew the agreement.
 In other countries, a number of years of marriage will result in the expiration of a marriage. In countries that have adopted the Uniform Premarital Agreement Act (UPAA), there is no sunset provision in the law, but one could be under private contract. Note that the states have different versions of the UPAA. The 2014 Report of the Legal Commission on Marital Property accepted the decision in cyclists in general and recommended the creation by Parliament of a “qualifying marriage agreement” that would create a fully binding pre-marital agreement as long as certain requirements were met. The Commission`s recommendations have yet to be implemented. 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] In general, marital agreements have a temporal element. Most will become effective on the day of the wedding and will last indefinitely.