Under Dutch law

Law of the Netherlands

The Netherlands is a civil law country. Its laws are written and the application of customary law is exceptional. The role of case law is small in theory, although in practice it is impossible to understand the law in many fields without also taking into account the relevant case law...

 a samenlevingscontract is a written agreement loosely translating to "cohabitation agreement

Cohabitation agreement

A cohabitation agreement is a form of legal agreement reached between a couple who have 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...

". It has been compared to marriage, but merely governs the so-called property relationships between two or more people who are cohabiting. It does not necessarily imply a marriage-like (or sexual) relationship exists, but the contract can include agreements about any children within the cohabitation arrangement.

Since the 1980s the contract has been popular among two different groups in Dutch society: people who wanted to formalise their relationship, but did not want to marry, and people who wanted to marry but could not legally do so. With the introduction first of registered partnerships and later the broadening of marriage to include gay and lesbians in the Netherlands

Netherlands

The Netherlands is a constituent country of the Kingdom of the Netherlands, located mainly in North-West Europe and with several islands in the Caribbean. Mainland Netherlands borders the North Sea to the north and west, Belgium to the south, and Germany to the east, and shares maritime borders...

, the need for a samenlevingscontract for the latter has become less pronounced.