Family reunification without marriage?

Can the partner of an EU citizen live in Belgium if the couple are neither married nor legally cohabiting? May a Brazilian student join his French girlfriend in Belgium? And what about an Italian woman with no resources of her own who follows her Dutch boyfriend to Brussels? The answer to these questions is often less obvious than one might think. Suddenly the municipality asks for evidence of a relationship, evidence that nobody ever kept, or the relationship is found to be too recent. Below, we outline the conditions and offer some practical tips for EU citizens and their de facto partners.

Anyone who wants to live in Belgium with a European partner usually thinks first of marriage or legal cohabitation. Although both routes can lead to family reunification, the conditions differ. While marriage does not require a relationship of any minimum length, legally cohabiting partners must in principle have lived together for at least one year or have known each other for at least two years. We discuss those conditions in a separate article.

The problem: couples in a serious but still young relationship, or who do not yet live together, often fail to meet these thresholds. Is there another option? Belgium and the European Union also provide a third route. Under it, a right of residence can also be obtained for the partner with whom the EU citizen has what is known as a “durable relationship, duly attested”, without marriage and without registration. What are the conditions for such a right of residence?

Conditions for the de facto partner of an EU citizen

Anyone who does not hold the nationality of a Member State of the European Union is a third-country national in immigration law. A third-country national who is the de facto partner of an EU citizen can obtain a right of residence of more than three months in Belgium, provided the following conditions are met.

1. Your partner has a right of residence of their own. Your right derives from that of your partner and from their status as an EU citizen. The EU citizen must therefore be entitled to reside in Belgium for more than three months themselves, for example as an employee or a self-employed person, or because they have sufficient resources of their own and health insurance (Article 40, § 4 of the Aliens Act).
2. Your relationship is durable. The law requires “a durable partner relationship, duly attested” (Article 47/2, 1° of the Aliens Act). In assessing this, the authorities must take into account the “intensity, the duration and the stable nature of the ties between the partners” (Article 47/3 of the Aliens Act). Because the law offers little clarity on this point (when is a relationship ‘intense’?), this condition is the main stumbling block. Below, we therefore offer a few pointers.
3. Your relationship is exclusive. Neither partner may be in a durable relationship with anyone else. Nor may they be so closely related that a marriage between them would be prohibited.
4. You are not a registered partner. This scheme applies to partners who are not in a legal cohabitation. Anyone who has registered a legal cohabitation is in principle covered by the scheme for legally cohabiting partners, with its fixed thresholds.
5. You accompany your partner to Belgium or join them here.

Applying the rules

What does this mean for the examples in our introduction? The Brazilian student can join his French girlfriend, provided that she herself has a right of residence in Belgium and he shows that their relationship is durable. The fact that he is here as a student is no obstacle. If anything, it is an asset, because it allows him to submit the application while his permission to stay is still valid.

The Italian woman is in a different situation. She is an EU citizen herself and therefore has her own right to reside in Belgium. If she does not work here, she must have sufficient resources and health insurance. Thanks to the case law of the Court of Justice and the subsequent legislative amendments, however, those resources need not come exclusively from the EU citizen herself. Her Dutch boyfriend can therefore provide for her financially.

What is a ‘durable partner relationship’?

In practice, a de facto partner’s application almost always comes down to two questions. Is the relationship too short? And is it truly durable?

No minimum duration, but a critical eye

Although the law does not impose a minimum duration, the Immigration Office still regularly assesses applications against the thresholds for legal cohabitation (living together for one year or knowing each other for two years). The Council for Alien Law Litigation (CCE) has held, however, that the authorities thereby add a condition that is not in the law (CCE 22 December 2022, No. 282 325). A short relationship therefore still stands a chance. Its brevity may nonetheless be taken into account, and must therefore be offset by the intensity and stability of the relationship.

What makes a relationship durable?

What counts is a romantic relationship, not a friendship or a house-share. Living together before the application is not a requirement. You must, however, show that there is a shared life, and that this life has a future. Here, the evidential weight of your documents makes the difference. A recent judgment shows how strict the authorities can be. A couple with twins, registered at the same address, were nevertheless refused. The Council annulled that decision because the authorities had weighed the documents separately instead of looking at them as a whole (CCE 16 October 2025, No. 334 356). Moreover, documents that the couple only produced on appeal no longer counted. Anyone who waits until after a refusal to put their file in order is therefore often too late.

Practical tips

1. Submit your application while your permission to stay is still valid. If you are already lawfully resident in Belgium, for example as a student or employee, you submit the application to your municipality. Following a positive residence check, you will receive a certificate of immatriculation, which covers your stay for as long as the application is pending. Anyone who waits until their residence card has expired makes things unnecessarily difficult for themselves.
2. Start with your partner. Your right depends on theirs. So first check on what basis the EU citizen is residing in Belgium. If they live on their own resources, they must also show that those resources and their health insurance are sufficient for you as well. If your partner is registered on the wrong basis, this can undermine an otherwise strong application.
3. Tell one story. A loose pile of photos and messages invites the authorities to find each document wanting on its own. So bring your documents together in a chronological overview that shows how your relationship has grown.
4. Submit all documents before the decision. In principle, the authorities decide within six months. Anything that strengthens your relationship in that time belongs in the file. Anything that only comes to light on appeal no longer counts.

How can we help you?

An application as a de facto partner is more complex than it seems, because the law leaves the authorities a wide margin of discretion. Fortunately, you do not have to do this alone. DECKER LAW can assist you in several ways. We examine which route is open to you in your situation and whether your partner is residing in Belgium on the right basis. We then select the documents that make the strongest case for your relationship and use them to build a coherent file, with a well-reasoned covering letter. Where possible, we keep a second avenue open, so that your residence does not depend on a single application. If your application is nevertheless refused, we work with specialist lawyers to defend your interests on appeal.