Yes. By way of example, NYC Prenup prepares both cohabitation agreements and postnuptial agreements for New Yorkers.
A cohabitation agreement is legal agreement between a couple who has chosen to live together. In some ways, such a couple may be treated like a married couple, such as when applying for a mortgage or working out child support. However, in some other areas, such as property rights, pensions and inheritance, they are treated differently. A cohabitation agreement contains documentation for a couple who wants to live together to protect themselves from unnecessary cost and litigation should their cohabitation break down. They can state regulate their intentions for property rights and what arrangements might be made for mutual financial support, dealing with debt, caring for children, etc. The agreement allows the individuals to determine in advance who will keep specific assets and what will happen to assets that have been purchased jointly if they separate. This agreement is intended to legally bind both parties.
A postnuptial agreement assists a married couple to help resolve issues in their marriage by removing a source of disagreement over finances, assets, children, chores, etc. Postnuptial agreements are also used by spouses as a way of controlling certain behaviors, such as adultery or over spending. Another reason to create a postnuptial agreement is if the financial status of either spouse changes after their wedding. Changes in a career, receiving an inheritance, experiencing a change in investment income, selling a business, etc. are all valid reasons to want a postnuptial agreement. For some couples a postnuptial agreement can stop conflict and promote harmony in their marriage.