Increasing numbers of unmarried cohabiting parents: new research highlights legal issues

The number of couples in the Netherlands living together without being married or in a registered partnership has been growing for years. In 2025, this figure stood at over 1.1 million couples in the Netherlands. Many of them have children. What happens if they split up? And what financial problems might arise as a result, not only for the parents but also for the children?

A new study by the University of Groningen and VU University Amsterdam, commissioned by the Scientific Research and Data Centre (WODC), aims to answer these questions.

Cohabiting couples not afforded the same protection as married couples

There is currently no legal framework for this group of ‘informally cohabiting couples’, unlike that which exists for married couples and registered partners. Mark Beuker, assistant professor of notarial law at the University of Groningen (RUG): “If you are married, all sorts of matters are regulated during and at the end of the relationship: joint asset accumulation, spousal maintenance, the equalisation of pension rights, social security benefits, taxes, inheritance and efficient procedural law. But if you cohabit, many matters are not dealt with automatically, and not everything can be covered in a cohabitation agreement.”

This can give rise to a variety of problems. Consider situations where the property is registered in the name of only one partner, or where agreements on childcare and financial contributions have not been made and set out in writing. Furthermore, legal proceedings at the end of the relationship can be more complicated than in the case of a marriage or registered partnership because there are no specific provisions laid down in law.

Do people part ways amicably?

But exactly how this plays out in practice remains unclear. Beuker: “At the moment, we’re mainly seeing court cases involving relatively higher incomes and assets. But there’s a whole category of people with fewer resources whom we don’t have a clear picture of.”

The research focuses in particular on cohabiting partners with children. Beuker: “You see that parents who separate often experience a decline in their standard of living. If the division of possessions between parents is poorly organised and there is no maintenance, this can have additional consequences for the children.”

The researchers aim to identify the financial and property law issues parents face during and after a relationship breakdown. To this end, they are drawing on existing research and data from Statistics Netherlands (CBS), as well as new empirical research among (former) cohabiting couples and legal professionals.

Autonomy is a key factor

They are also examining possible solutions, including both legal measures and other provisions that could prevent or resolve such problems. “In discussions on this topic, autonomy plays an important role: it may well be that people make a very conscious choice not to make arrangements. However, we know from international research that people have an overly rosy view of their relationship and often do not consciously choose to cohabit without marriage rather than getting married. They then put off making arrangements until it is too late.”

The WODC study is being carried out by an interdisciplinary team of family law and inheritance law specialists: alongside Mark Beuker, these include Professor of Notarial Law Leon Verstappen, Associate Professor of Notarial Law Irene Visser (both from the University of Groningen), Assistant Professor of Private Law Alexander Flos and Professor of Private Law Masha Antokolskaia (both from VU University Amsterdam).

The final report will be published by April 2027 at the latest.