The myth
Surveys repeatedly find that a large share of the public believes living together for long enough creates a "common-law marriage". In most countries it does not. Cohabiting couples are the fastest-growing family type across the English-speaking world — and the least protected.
Three models, and where the line falls
Broadly, three approaches coexist:
- No status at all. Cohabitation creates nothing: no share of property in your partner's name, no maintenance, no automatic inheritance, no pension rights in many schemes. Claims fall back on ordinary property law — proving a beneficial interest — which is slow, difficult and expensive.
- A limited redress scheme. After a qualifying period, or where there is a child, a financially dependent partner can ask a court for a financial award on separation, and sometimes on death. These schemes usually carry very short time limits, which is what defeats most claims.
- Near-equivalence with marriage. After a defined period, or with a child, the couple is treated substantially like a married couple for property division and maintenance.
Which model applies to you is the single most consequential fact on this page, and it changes at the border — and sometimes at a state or provincial line within the same country.
What it does not change
Parental status is unaffected: children have the same rights regardless of their parents' marital status. How an unmarried father acquires parental responsibility does vary, and it is worth confirming rather than assuming.
How to protect yourselves without marrying
- A cohabitation agreement setting out contributions, ownership shares and what happens on separation.
- A declaration of trust when buying property together, recording each party's share — especially where deposits are unequal.
- Wills on both sides: without one, your partner may inherit nothing (see inheritance and wills).
- Nominations on pensions and life insurance, which pass outside the estate.
- A registered partnership where one exists, which gives legal protection without marriage.
On separation
No procedure is needed — you simply separate. The difficulties arise over jointly owned property and unequal contributions, which is why keeping records of who paid what, and agreeing the position in advance, matters far more for unmarried couples than for married ones.
What the law provides: the example of France
The French Civil Code defines cohabitation (concubinage) as a de facto union, marked by a stable and continuous shared life, between two people of different sexes or of the same sex (French Civil Code, art. 515-8). No formality is needed to be cohabiting partners: the shared life can be proven by any means, for example bills or statements from relatives and friends (Service-public.fr, 2026).
Rented housing. If only one of you signed the lease, the other is not a tenant: when the signatory gives notice, the other must leave at the latest when they do. In privately rented unfurnished housing, however, the partner can have the lease transferred when the signatory dies or abandons the home (a sudden, unforeseeable departure, or one made unavoidable by their health), provided the relationship was publicly known and they had lived together for at least one year (Service-public.fr, 2026).
Passing on assets. What a cohabiting partner receives under a will is taxed at 60%, the rate that applies between unrelated people (French General Tax Code, art. 777). Life insurance escapes this scale: for premiums paid since 13 October 1998 while the insured person was under 70, each beneficiary is entitled to an allowance of €152,500, then a 20% levy up to €700,000 and 31.25% above that; older premiums, or premiums paid after 70, follow other rules (impots.gouv.fr, 2026).
Children. Parental authority is exercised jointly by both parents. But if parentage is established for the second parent more than a year after the birth, or is declared by a court, the first parent exercises it alone (the article also provides for a specific case of medically assisted reproduction); joint exercise then requires a joint declaration to the court registry or a decision by the family judge (French Civil Code, art. 372).
When living together means sharing: the example of New Zealand
In New Zealand, unmarried couples who have lived together for more than three years fall under the same law as married couples: on separation, their relationship property is divided equally, unless the court considers that extremely unfair (New Zealand Ministry of Justice, 2026). Below three years, the law does not normally apply: the court can order a division only if there is a child of the relationship or the applicant made a substantial contribution, and if failing to do so would cause serious injustice; each partner's share then depends on their contribution (Property (Relationships) Act 1976, s 14A).
The law differs between countries
This topic falls under the same framework as partnerships and cohabitation, whose main page carries a detailed entry for each of the twenty countries covered.
