Part Three — The Legal Reckoning

The Cohabitation Experiment

Cohabitation

Chapter 8 described the default terms of the marriage container — what you signed, what you owe, what you take with you when you leave. This chapter asks: if you don't enter that container, what are the alternatives? What do they look like, and where have they fallen short?

The answer is not encouraging. In many European countries, cohabitants remain legally precarious. Some jurisdictions — France's PACS, the Nordic countries, Belgium — offer partial frameworks, and the Netherlands offers registered partnership. But a great many couples fall outside any of them. They can live together for twenty years, buy a house together, raise children together, and when one dies or the relationship ends, the law treats them as if they never existed. This is not only an oversight. It is, at least in part, design — the same defense of marriage's "special status" that we will see in Poland.

Poland: What a Veto Denied

In 2026, Polish President Karol Nawrocki vetoed legislation aimed at establishing a legal status for unmarried couples. (The following account is drawn from public reporting at the time; the quotes should be verified against primary sources before formal publication.) The bill — pushed by Prime Minister Donald Tusk's centrist government — would have allowed two adults, regardless of gender, to sign a cohabitation agreement before a notary and register it at the civil registry office. Signatories would have gained a range of rights: joint tax filing, exemption from inheritance and gift taxes, access to medical information, health insurance coverage, survivor's pensions, and the right to arrange a partner's funeral.

This sounds like common sense. Nawrocki disagreed. In his veto statement, he said the bill "creates a new, formalized family law institution, equipped with an extensive catalogue of rights similar to marriage." He further declared: "As guardian of the Constitution, I cannot accept a solution that would lead to the loss of the special status of marriage — Article 18 of the Constitution defines marriage as a union of a man and a woman, under the protection and care of the Republic of Poland."

Polish Equality Minister Katarzyna Kotula responded that Nawrocki had, in her words, "turned his back on the millions of people living in informal relationships today" — a figure reported by her ministry, though estimates of the number of cohabiting Poles vary. The Polish Campaign Against Homophobia noted that the vetoed bill was "merely a fragment of the first version of the document — the one dealing with civil partnerships" — and that "today's veto shows that even the minimum rights the bill sought to provide are too much for the president."

The significance of this case extends beyond Poland. It echoes a broader tendency across Europe: when legislators attempt to create even a basic legal framework for cohabitation, opposition often frames it as an attack on marriage. Nawrocki's veto logic is: if cohabitants gain marriage-like rights, marriage is no longer "special." Translated: to keep marriage special, others must remain in a legal vacuum.

A note on scope: the detailed legal mechanics that follow are drawn from the Netherlands, whose system is unusually clear and well-documented. The structural issues — default regimes, the cohabitation void, the cost of remaining informal — are broadly comparable across Western jurisdictions, though the specifics differ country by country.

The Netherlands: Freedom's Price Is Vulnerability

The Netherlands looks more progressive. In 1998, it introduced registered partnership (geregistreerd partnerschap), which enjoys nearly all the rights of marriage. In 2001, it became the first country in the world to open marriage to same-sex couples. On paper, this is a pioneer's story.

But the legal framework reveals a deeper truth: the Dutch system offers two paths — marriage or registered partnership — and a third path that is essentially unprotected.

Registered partnership is nearly identical to marriage. Partners automatically inherit from each other, have pension rights, and share parental authority over children born during the union. The key differences are procedural: no mandatory "I do" ceremony, and dissolution can occur without a court if there are no minor children — through a notary or lawyer instead. The legal substance is the same.

Cohabitation without formalization is a different universe. In the Netherlands, there is no principle of "common law marriage." How long you live together does not automatically create any rights or obligations. Without a cohabitation agreement, cohabitants have no automatic right to spousal support, no claim to each other's pensions, and no inheritance rights.

The numbers tell the story. In 2024, the Netherlands had 1.12 million unmarried cohabiting couples, compared to 3.25 million married couples, according to Statistics Netherlands (CBS). Of the unmarried couples, 469,620 had children. Nearly half a million couples are raising children together without the automatic legal protections that marriage provides.

The most painful scenario is inheritance. Two cohabitants buy a house together, each owning half. One dies unexpectedly. Because they were not married, had no registered partnership, and no cohabitation agreement, the deceased's estate is divided according to law. The deceased's children — perhaps from a previous relationship — inherit a portion of the house. The surviving partner suddenly finds themselves sharing ownership of their own home with people they may not even know. They cannot decide independently about the home. They may be forced to leave or sell.

A cohabitation agreement with a "residence clause" or a properly drafted will could prevent this. But most people do not know they need these documents. They believe living together is enough. It is not.

The Cohabitation Contract: Protection You Have to Build Yourself

Since the law provides nothing automatic for cohabitants, everything must be arranged through a cohabitation agreement (samenlevingscontract). This document can cover:

Division of household expenses
How to handle investments in joint property and home ownership
Agreements on spousal support in the event of separation
Pension rights

But a cohabitation agreement does not provide the same protections as marriage or registered partnership. For inheritance, cohabitants must make separate wills. They do not automatically inherit from each other, even with a cohabitation agreement.

The process is also fragile. Ending the cohabitation itself can be as simple as a registered letter; but dividing any jointly owned property or untangling shared finances still requires a legal process.

For pension rights, the requirements are even more specific. To receive partner pension as a cohabitant, you typically need a notarized cohabitation agreement, and even then, the pension fund may impose additional conditions. Cohabitants do not automatically become each other's partners in pension schemes — that only happens through marriage or registered partnership.

The Financial Trap of Informality

The absence of legal protection is not just an abstract concern. It translates into concrete financial harm.

Consider a couple who buy a house together. One partner contributes €80,000 to the purchase price; the other contributes nothing. They take out a joint mortgage for the remainder and make no other arrangements. After ten years, they separate and sell the house for €500,000. Without a cohabitation agreement addressing unequal investments, a judge will often rule that each partner is entitled to half — €250,000 — regardless of who paid more. Dutch law does not automatically regulate compensation rights for cohabitants, though unjust-enrichment claims are sometimes possible in exceptional cases. The person who invested more is not automatically entitled to compensation.

This is the freedom of cohabitation: freedom from the marriage container, and freedom from most legal remedy when things go wrong.

What the Dutch Model Reveals

The Netherlands is often held up as a progressive example. And in some ways, it is. Registered partnership offers a genuine alternative to marriage. Same-sex couples have full marriage rights. The legal framework is more flexible than in many countries.

But the Dutch model also reveals the limits of reform. It offers two paths — marriage and registered partnership — that are nearly identical in substance. And it leaves a growing number of cohabitants without automatic protection. The system assumes that if you want rights, you should formalize your relationship. But it does not ask whether the available forms of formalization match how people actually want to live.

The result is a two-tier system: those who marry or register, and those who don't. The first tier has rights. The second tier has a registered letter.

Across both cases — the Polish veto that blocks even minimal rights, and the Dutch system that still leaves a growing share of cohabitants unprotected — runs the same thread: the law continues to defend marriage's "special status" by keeping everyone outside it vulnerable.

The Gap Between Law and Life

The cohabitation experiment is not, on the whole, a failure. It is a partial success — people are living together, raising children, building lives — that has exposed a deeper problem: the law has not kept pace with how people actually structure their intimate lives.

More people are choosing cohabitation. More children are being raised in unmarried households. More couples are building lives together without formalizing their relationship in ways the law recognizes. And the law, in most jurisdictions, offers them nothing automatic.

The choice is not between marriage and anarchy. It is between a legal system that recognizes only one form of committed partnership, and a legal system that recognizes the diversity of how people actually live. The first produces vulnerability. The second requires imagination.

The next chapter explores what that imagination might look like — and what it would take to build legal frameworks that match the reality of modern relationships.