Stable Union (União Estável) in Brazil: What Changes for a Couple’s Property and How to Protect Each Partner

This page is a translation of the original Portuguese text, provided for convenience. It deals with Brazilian law. If there is any discrepancy, the Portuguese version prevails. Read the original in Portuguese

A stable union (união estável) produces significant legal effects from the moment a couple begins living together with the intention of forming a family, even without any formal registration. Understanding how it comes into being, which property rules apply, and why the cohabitation agreement has become an essential tool can help you avoid painful disputes if the couple separates or one partner dies.

What defines a stable union and when it begins

A stable union is a public, continuous, and lasting relationship between two people who live together with the goal of forming a family. Unlike marriage, it requires no certificate, no ceremony, and no minimum length of time together. What matters is that all of these elements are present in fact, showing that a true family unit exists and not simply a dating relationship or an occasional one.

The Civil Code recognizes this form of family in Article 1.723. The rule dispenses with formal requirements precisely because the reality of shared life comes before the paperwork. That is why many couples are in a stable union without knowing it, accumulating rights and obligations that only come to light when the relationship ends or when one of them dies.

A relationship being public does not mean putting it on display. It is enough that the couple presents themselves socially as partners and that they share a home, bills, and life plans. Continuity rules out relationships that are constantly broken off, and duration shows stability, even though the law does not set an exact number of years.

Property effects and the applicable property regime

The point that surprises people most concerns property. When the couple has not signed a document providing otherwise, the regime of partial community property (comunhão parcial de bens) applies to the stable union under Article 1.725 of the Civil Code. This means that everything acquired for value during the relationship belongs to both partners, half to each.

Assets that each partner already owned before the relationship remain separate property, as do assets received by inheritance or gift during the relationship. The rule seems simple, but its consequences run deep. A property purchased in the name of only one partner during the union becomes part of the shared estate and must be divided, even if the deed lists a single owner.

This automatic effect often catches couples off guard. People who live together for years assuming that each owns only what is in his or her own name discover, when the relationship ends, that the law presumes a division. That presumption protects whoever helped build the shared estate, including indirectly, by caring for the home and the family.

There are inheritance consequences as well. The surviving partner takes part in the deceased partner’s estate, sharing it with descendants and ascendants under the rules of succession. A death without advance planning often turns grief into litigation, especially when there are children from prior relationships or assets of significant value.

That is why many couples are in a stable union without knowing it, accumulating rights and obligations that only come to light when the relationship ends or when one of them dies.

The cohabitation agreement as a tool for predictability

It is precisely to avoid surprises that the cohabitation agreement (contrato de convivência) has taken on such importance. It is a document in which the partners set out in writing the property rules that will govern the relationship. They may choose to keep partial community property, opt for complete separation of property, or design an in-between arrangement tailored to the couple’s situation.

The agreement may be made as a private instrument or as a public deed before a notary office (cartório). The public form provides greater security and makes it easier to prove the agreement to third parties, banks, and the real estate registry itself. In the document, the couple declares that the union exists, states the start date whenever possible, and establishes the property regime they have chosen.

A clear agreement spares you from having to prove in court, years later, when the relationship began or what you intended regarding your property. The more detailed and honest the agreement, the less room there is for conflict. It works like a map that guides the division of property and protects both partners.

It is worth noting that the chosen regime takes effect from the date the agreement is signed. It does not reach back to cover assets that were already subject to division, unless there is an express and valid provision saying so. That is why formalizing the relationship early is a strategic decision, not a mere bureaucratic whim.

Practical differences between the regimes and how to decide

Each property regime suits a different kind of couple. Under partial community property, the default rule, the guiding idea is shared effort during the relationship, with division of what the two built together. It is the choice that best reflects relationships in which both partners contribute to growing their joint wealth.

Under complete separation of property, each partner keeps exclusive ownership of whatever he or she acquires, with no sharing of assets. This regime tends to appeal to people who already have established wealth, who work as business owners, or who want to protect children from earlier relationships. Separation, however, requires understanding that there will be no automatic division when the relationship ends.

It is also possible to combine rules, as long as legal limits are respected. The couple may, for example, keep business assets separate and share only the assets of their household life. The freedom to agree on terms is broad, but the agreement must be well drafted from a technical standpoint to avoid being declared void.

The decision about the regime should not be made on the emotion of the moment alone. We recommend that partners list their current assets, plan for future purchases, and talk openly about debts, businesses, and children. A well-considered choice today saves years of argument tomorrow.

Couples who skip this planning end up bound by the general rule. There is nothing wrong with adopting partial community property, as long as it is an informed choice. The problem arises when half of the property is divided without anyone ever having thought about it, turning the breakup into a tense negotiation over every asset.

Precautions when formalizing and protecting the relationship

If you want to put your stable union in order, you should gather personal documents, proof of a shared residence, and any evidence of life together, such as joint accounts and photographs. These items help establish the start date, which directly affects which assets are subject to division.

The next step is to seek legal advice to draft the cohabitation agreement precisely. Generic clauses, or clauses copied from ready-made templates, often fail when they meet the complexity of real life. A well-prepared document anticipates scenarios such as separation, death, the purchase of real estate, and responsibility for debts.

It is also wise to review the agreement whenever something significant changes, such as the birth of a child, the purchase of a home, or the opening of a business. The relationship evolves, and the document that governs it needs to keep pace to remain useful and up to date.

Frequently Asked Questions

Do I need a minimum period of living together to have a stable union recognized?

The law sets no fixed period. A stable union exists when the relationship is public, continuous, and lasting, and the couple lives together with the intention of forming a family. Time is only one sign of stability, and relationships of just a few months can be recognized if they clearly show a family purpose and an actual shared life.

If we don’t sign an agreement, which property regime applies to our union?

In the absence of a cohabitation agreement, partial community property applies automatically. This means that everything acquired for value during the relationship will be divided in half, regardless of whose name the asset is registered in. Assets owned before the union, and those received by inheritance or gift, remain separate property.

Can the cohabitation agreement change the rules at any time?

The partners may change the property regime by signing a new agreement, within legal limits and respecting rights that have already been established. The change takes effect from the date of the new agreement and, as a rule, does not reach back to undo earlier property situations. That is why formalizing early, and reviewing the agreement when important changes occur, is the safest course.

As informações deste artigo são de caráter informativo e não substituem consulta jurídica individualizada. Cada caso possui particularidades que exigem análise específica.