Breaking up with your unmarried partner: the flat, the assets and the money

The case, in five lines

What is brought

Action for division of the jointly owned flat (actio communi dividendo, articles 400 and 404 of the Código Civil), action for reimbursement between joint and several co-debtors of the mortgage (article 1145) and, if there are minor children, a claim on custody, maintenance and use of the home (articles 748.4 and 770 of the Ley de Enjuiciamiento Civil, the Civil Procedure Act). Only exceptionally, an action for unjust enrichment.

Before which court

The Tribunal de Instancia (the first-instance court). The children's matters go before its sección de familia, infancia y capacidad (family, childhood and capacity section): that of the last common home or, if the parents live in different judicial districts, at the claimant's choice, that of the defendant's home or of the child's residence (article 769.3 of the Ley de Enjuiciamiento Civil). The division of the flat and the reimbursement go in separate proceedings, and the division always as a juicio verbal, oral proceedings (article 250.1.16).

Deadline

The division of the flat never becomes time-barred between co-owners (article 1965 of the Código Civil). Reimbursement of what was overpaid is time-barred after five years (article 1964.2), which it is wise to count from each payment, and the period is interrupted by an out-of-court claim. In Catalonia, compensation for work and maintenance between cohabitants are time-barred one year after the stable couple ends (article 234-13 of the Catalan Civil Code).

Who can bring it

Either cohabitant against the other, as co-owner of the flat and as co-debtor of the loan. In the proceedings on the children, either parent, with the Ministerio Fiscal (the Public Prosecutor) taking part because there are minors. The bank is not a party and keeps its right to recover the whole debt from either of you.

Financial risk

Without agreement, the division ends in an auction open to outside bidders, and a flat with a live mortgage or with its use granted to a minor sells far below market value: you both lose. In the division and in the reimbursement claim the general rule is that the loser pays the costs, and a compensatory pension sought by analogy under the general law is dismissed. Meanwhile, the loan remains joint and several.

No wedding, no community of property: each asset belongs to whoever bought it

The first piece of news is often a surprise: registration in a registry of unmarried couples creates no matrimonial property regime. Under the general law there is no community of property between cohabitants, and the Tribunal Supremo (the Supreme Court) has held, since a plenary judgment of 2005, that the rules of marriage cannot be applied by analogy to people who chose not to marry. What each of you acquired in your own name is yours; what you bought together is ordinary co-ownership governed by articles 392 onwards of the Código Civil.

That co-ownership has two rules that decide many cases. Article 393 presumes the shares to be equal unless the contrary is proved and requires each participant to bear profits and charges in proportion to their share. That is why the deed rules: if it says «in halves», each of you owns half even if one put in more money, and the difference can only be claimed as a debt, never as more square metres of flat. With bank accounts the opposite happens: the Tribunal Supremo has held that joint holding gives power to operate the account, not ownership, and the money belongs to whoever paid it in.

There are two exceptions worth knowing before giving anything up for lost. The first is an agreement: cohabitants can set down in writing what happens to their assets if they separate, and that agreement binds like any contract. The second is an intention to make certain assets common inferred from conclusive conduct, which the Tribunal Supremo accepts exceptionally when the behaviour of both reveals it beyond doubt, never merely from living together. And if the flat belongs to only one of you and there are no children, whoever stays without title occupies it on sufferance and can be evicted through a juicio verbal (article 250.1.2 of the Ley de Enjuiciamiento Civil).

The jointly owned flat: you can seek its division whenever you wish

Article 400 of the Código Civil is categorical: no co-owner is obliged to remain in co-ownership, and each may at any time ask for the common property to be divided. Article 1965 adds that between co-owners this action never becomes time-barred. There is no legal rush to bring it, and no way for your former partner to block it indefinitely. The only exception is an agreement to keep the flat undivided, which article 400 itself limits to ten years, extendable by a new agreement.

A flat is essentially indivisible, so article 404 offers two ways out: awarding it to one of you who compensates the other, if both agree, or selling it and sharing the price. Without agreement, it is sold at public auction, and it is enough for one of you to ask for outside bidders to be admitted (articles 406 and 1062 of the Código Civil). Since 20 March 2024 this claim always proceeds as a juicio verbal, whatever the value of the flat (article 250.1.16 of the Ley de Enjuiciamiento Civil). And before filing it, article 5 of LO 1/2025 requires an attempt at an appropriate dispute resolution method on that same subject matter; without the document proving it, the claim is not admitted.

What nobody tells you is that the auction is the worst outcome for both of you. A flat with a live mortgage, with occupants or with its use granted to a minor is knocked down far below its market value, and whatever is lost is lost by both. That is why the division claim is almost always the tool that forces a serious negotiation: one of you buying out the other's half, or an agreed sale to a third party. The firm prepares it with an expert valuation fixing the real value and with a specific proposal for allocation.

The mortgage: the bank can pursue both of you, and you can claim back

The break-up changes nothing as far as the bank is concerned. If the loan is joint and several, as almost all loans signed by couples are, the lender can claim the whole instalment from either of you (article 1144 of the Código Civil), and a private agreement of «you keep the house and the mortgage» does not bind it: replacing one debtor with another requires the creditor's consent (article 1205). Until the bank expressly releases one of you, you both still owe the whole amount.

Between the two of you, on the other hand, each answers for their own share. Article 1145 allows whoever pays to claim from the co-debtor the share that corresponds to them, with interest on the advance, and articles 393 and 395 apportion the IBI (property tax), the community charges and the upkeep costs in the same way. That is the answer to «the mortgage is your problem»: whoever stays in the flat, even with its use granted by a judgment, still owes their half of the loan, because the instalment pays for property owned by both and is not child maintenance.

The clock is what sinks most cases. A claim for what was overpaid is a personal action and is time-barred after five years (article 1964.2 of the Código Civil). The most prudent reading counts the period from each payment, because it could be demanded from that day; some courts place it at the break-up, but building the case on the favourable theory is a gamble. A burofax (certified letter) claiming specific amounts interrupts the limitation period (article 1973) and, if it proposes a solution, also serves as the negotiation attempt. And beware of the deposit: if you put in more and still signed the purchase in halves, the other side will argue that the difference was a gift, and without a document or a message saying otherwise that defence is hard to rebut.

With children, the flat is decided in two separate proceedings

If there are minor children, custody, maintenance and the use of the home are decided in a family case of their own, the one dealing exclusively with custody and maintenance of minor children (article 748.4 of the Ley de Enjuiciamiento Civil), which follows the rules of article 770 before the sección de familia, infancia y capacidad of the Tribunal de Instancia, with the Ministerio Fiscal as a party. Use of the home is governed by article 96 of the Código Civil, which the courts apply to the children of unmarried couples because it protects the child, not the marriage. How that use is granted and limited is explained in our guide on the family home; what matters here is how it interacts with the division.

This is the procedural trap that wastes the most time. The law allows spouses to join the division of the flat to their divorce (article 437.4.4 of the Ley de Enjuiciamiento Civil), but that exception refers only to spouses in matrimonial proceedings. For an unmarried couple there is no shortcut: the children go in one set of proceedings and the flat in another. And the prior negotiation requirement in article 5 of LO 1/2025 covers both, because proceedings on custody and maintenance are not among the exempted matters; the measures under article 158 of the Código Civil, interim measures sought before the claim and enforcement are left out. A single negotiation covering children, use, flat and sums of money meets the requirement for every claim if the subject matter is the same.

Granting the use of the home does not prevent division. The Tribunal Supremo has held that a co-owner can bring the division action even if the use has been granted to the other and the children, but whoever buys will have to respect that use, and the restriction it imposes is entered in the Registro de la Propiedad, the Land Registry (article 96.3). With a six-year-old girl, that means a flat nobody will pay market price for. The sensible strategy is to settle the use in the family proceedings (its duration, shared custody that changes the picture, an agreed sale date) and to use the division as leverage to close the buy-out of the half or the sale, not as a weapon to remove a child from her home.

There is no compensatory pension between cohabitants

The threat to claim a pension «as if you were married» goes nowhere under the general law. Article 97 of the Código Civil refers to the spouse for whom separation or divorce causes an economic imbalance, and the Tribunal Supremo refuses to extend it by analogy to unmarried couples: those who did not marry did not take on the status of marriage, neither its burdens nor its advantages. A claim for that pension under the general law is dismissed, and whoever brings it risks paying the costs.

The route that does exist is exceptional: unjust enrichment. It requires proof that one party was enriched, that the other was correspondingly impoverished and that there is no cause justifying it. It fits, for example, where one partner worked unpaid for years in the other's business, or gave up a career to keep the household going while the assets grew only in the partner's name. It does not fit where both worked and shared expenses. It is a personal action, time-barred after the five years of article 1964.2, and it requires prior negotiation like any civil claim.

This works in both directions. If you are the one who stopped working or who kept the household going, your case is not built on the word «pension» but on proof of the imbalance: employment record, lost income, work in the other's business, contributions to the other's assets. If you are the one receiving the threat, the answer is not to deny the relationship but to demand that the enrichment and its cause be specified. Either way, what you signed while living together is worth more than any case law: a cohabitation agreement providing for compensation is enforced like any contract.

If regional civil law applies, the rules and the deadline change

Everything above is the general law. Catalonia, Aragon, Navarre, Galicia, the Basque Country and the Balearic Islands have their own laws on stable or unmarried couples, and several of them provide, with differing requirements, for economic compensation or pensions after the break-up. Which one applies depends on the cohabitants' vecindad civil (regional civil status) and, in several, on registration in their registry or a minimum period of cohabitation, so the first thing the firm checks is which law governs your relationship.

The Catalan case is the most surprising because of the deadline. The Catalan Civil Code grants a cohabitant economic compensation for work and a maintenance payment, but its article 234-13 provides that those rights are time-barred one year after the stable couple ends, and that they must be claimed in the same proceedings in which the other effects of the ending are decided. Anyone who waits to see how the break-up settles may lose them.

Conversely, the Tribunal Constitucional (the Constitutional Court) has struck down provisions of regional laws that imposed economic effects on couples who had not agreed to them, out of respect for the freedom not to marry, and most of the property regime in the Valencian law on unmarried couples fell for lack of competence. In the Comunitat Valenciana and in Madrid, therefore, property relations are resolved under the Código Civil and whatever you agreed. Registration in an administrative registry does not, by itself, change the ownership of anything.

How we run the case, step by step

1. 1

   Establish what belongs to whom and which law applies

   We read the purchase deed, the loan deed and the land registry extract, and check both partners' vecindad civil, the registration and whether any cohabitation agreement exists. That reading shows whether the case falls under the general or a regional law and which deadline is running.

2. 2

   Stop the clock with a certified letter

   We claim in writing the specific amounts overpaid, instalment by instalment, and propose an overall settlement. The claim interrupts the five-year limitation period and leaves a reliable date for the break-up.

3. 3

   Negotiate the whole package and keep proof

   The firm conducts the negotiation required by article 5 of LO 1/2025, with the same subject matter the claims will later have: children, use, fate of the flat and reimbursements. Whatever is agreed about the children is taken to the court for approval.

4. 4

   Claim concerning the children

   Without agreement, the claim on custody, maintenance and use is filed before the sección de familia, infancia y capacidad, seeking interim measures if the situation cannot wait. It is the one that settles, for years, who lives in the flat.

5. 5

   Division and reimbursement claims

   The division claim is filed as a juicio verbal, with an expert valuation and an allocation proposal, and as a rule the claim for what was overpaid goes separately: as a juicio verbal up to 15,000 euros (article 250.2 of the Ley de Enjuiciamiento Civil) and as ordinary proceedings above that.

6. 6

   Sale or allocation and final settlement

   Once there is a judgment, the flat is awarded to one of you or auctioned. The price pays off the mortgage or a takeover of the loan is agreed with the bank, and whatever the other side owes you under the reimbursement judgment is recovered by attaching their share of the price.

The law that applies

• Art. 400 CC. No co-owner is obliged to remain in co-ownership and each may at any time ask for the common property to be divided; the only valid agreement is one to keep it undivided for a fixed period not exceeding ten years, extendable by a new agreement. BOE-A-1889-4763
• Art. 404 CC. If the property is essentially indivisible and the co-owners do not agree to award it to one of them who compensates the others, it is sold and the price shared. Pets are not divided by sale unless all agree; failing that, the court decides their fate in light of the co-owners' interests and the animal's welfare. BOE-A-1889-4763
• Art. 1965 CC. Between co-heirs, co-owners or owners of adjoining land, the action to seek partition of an estate, division of common property or the marking of boundaries never becomes time-barred. BOE-A-1889-4763
• Art. 1145 CC. Payment by one of the joint and several debtors extinguishes the obligation, and whoever paid can only claim from the co-debtors the share corresponding to each, with interest on the advance. BOE-A-1889-4763
• Art. 1964.2 CC. Personal actions with no special period are time-barred five years after performance of the obligation could be demanded. BOE-A-1889-4763
• Art. 250.1.16.º LEC. Claims bringing the action for division of common property are decided as a juicio verbal whatever their value, in the wording in force since 20 March 2024. BOE-A-2000-323
• Art. 437.4.4.ª LEC. Joinder of different actions is not allowed in a juicio verbal save for listed exceptions; one of them allows either spouse, in separation, divorce or annulment, to bring the action for division of common property at the same time. The exception does not extend to unmarried couples. BOE-A-2000-323
• Art. 5 LO 1/2025. Makes prior recourse to an appropriate dispute resolution method on the same subject matter, including negotiation between the parties or their lawyers, a condition for bringing a civil claim. It applies to the declaratory and special proceedings of the Ley de Enjuiciamiento Civil, save for the matters it lists, and not to enforcement claims or interim measures sought beforehand. BOE-A-2025-76

Each article checked against the consolidated text published in the BOE (the Spanish official gazette).

Frequently asked questions