What is the legal definition of a family?
The law defines family based not on a fixed concept, but on specific contexts such as marriage/civil partnership, blood ties, and functional dependency (e.g. children who are practically, financially and emotionally dependent on their parents).
Families come in all shapes and sizes. In a traditional and historical sense, a family was based on generations of a mother and father, their children, their children’s children, and so on. The ‘nuclear’ family is the most conventional style, meaning two parents and their children living under one roof. Extended family brings in aunts, uncles, grandparents, cousins and beyond, with some families stretching far and wide. In more recent decades, family structures have become more flexible, with stepparents, adopted children, blended families, single parent families and so on. Of course, with the increasing average age of marriage, and the falling birth rate, many families are also made up of humans and their pets (although legally this is unfortunately not the case).
Marriage and civil partnerships are no longer the only way to have a family, with more than 3.5 million unmarried couples living together in cohabiting relationships.
Those couples currently have limited legal recourse should their relationship end, despite often many years of financial, emotional and practical interdependence on one another including a shared home, finances and often shared children. As such, for many years legal professionals have been calling for reform for cohabiting couples , brought together by the Law Commission in a number of reports over the last two decades.
What is the legal definition of ‘an enduring family relationship’?
The concept of an ‘enduring family relationship’ originates specifically from the Adoption Act 2002, which states that eligible joint couples who can adopt should be married, civil partners, or same or opposite sex couples living together in an ‘enduring family relationship’. This has evolved over time within case law to be used in wider contexts. In the context of family law matters, an enduring family relationship has been argued to describe a stable, committed partnership that is like that experienced by married couples or civil partners. There are general expectations to evidence this, for example:
- A consistent period of living together
- A level of financial interdependence
- A shared home
- The presence of a sexual relationship
- External recognition of the relationship
There are, however, examples in case law of an enduring family relationship being acknowledged even where the couple do not physically live together.
Case example – Re E (Adoption by One Person) [2021] EWFC 45
One such matter involved two women who had previously been a cohabiting, unmarried couple. They had two children from the same sperm donor, and each had physically given birth to one. The non-birth mother had adopted the older child, and before the adoption for the second child could be finalised to make the other partner a legal parent, the couple separated.
The judge’s issue was whether the women still constituted an ‘enduring family relationship’ as referenced in the Adoption Act 2002, despite their separation. Both parents continued to play an active role in the children’s lives, were both the legal parents of their elder child, and maintained a strong co-parenting relationship. Ultimately, the judge ruled in favour of the adoption order applied for, arguing that in many modern relationships, couples ‘live apart together’.
He determined that the women were still a cohesive family unit despite there not being the presence of a romantic relationship between them, and the adoption order was in the child’s best interests.
How should an enduring family relationship be defined for cohabitation rights?
In the consultation document ‘A fairer end to relationships’, the Government put forward proposals for granting legal rights to unmarried, cohabiting couples, aiming to minimise economic disadvantage suffered by the financially weaker party, and prevent expensive, long-winded litigation under TOLATA claims. As part of this, they have acknowledged the need for specific criteria which would be considered by the family court if an ex-partner were to apply to court for financial relief following the end of a cohabiting relationship. Specifically, this references the concept of an enduring family relationship – families with and without children, and the Government has proposed that three years minimum continuous cohabitation would qualify for rights.
This is identified as being cohabitants who are in relationships that are:
- Romantic
- Committed
- Long-term
- Interdependent
Ciara Pugh, family lawyer and cohabitation specialist in our London family law office, explains:
“It is helpful to have this definition as a guide, without requiring an overly restrictive ‘tick box’ definition, as there are any number of types of cohabitation relationships that exist in modern society. However, there needs to be a degree of structure to the terminology, to avoid increased opportunity for litigation where individual parties may dispute whether they were in an enduring family relationship to begin with, before even getting to the financial claims aspect.
“A number of relevant factors have been proposed by the Government which would enable courts to define whether any specific partnership constituted an enduring family relationship, including:
- The existence of a joint household
- Stability of the relationship
- Financial arrangements
- Responsibility for children
- Presence of a sexual relationship
- Public recognition of the relationship
“All of these are sensible factors that should be taken into consideration. However, there are several elements that need additional thought based on how individual relationships work in day-to-day life.”
Should all criteria of an enduring family relationship apply to every cohabiting couple?
The criteria proposed by the Government have legal, historical and social roots that make them helpful in determining the level of a relationship, particularly if legal rights are introduced in the future for cohabitees. Yet, the courts will need to have a degree of discretion as not all criteria should apply to every cohabiting couple.
There are notable exceptions where these could increase litigation, be misleading or where there should be more flexibility.
For example, some elderly people decide to live together, often after the death of their spouses. There are several reasons for this, including companionship and sharing of costs. These people could become inadvertently caught up in legal frameworks they never intended to enter, potentially risking litigation or even inheritance disputes. Siblings are also increasingly choosing to live together as a saving exercise, or because they haven’t found the right romantic partner yet. They may well have a level of financial interdependence, and a shared household (often in joint names). Should their relationship break down, would a framework for legal rights be appropriate?
On the other hand, it should not be that the absence of a sexual relationship automatically excludes parties from making financial claims. Many couples live very happily together for the entirety of their relationship without having physical intimacy in this way. There are also cases, although relatively few, of ‘lavender relationships’, where a man and a woman will form a relationship even though one or both are gay.
Is an ‘enduring family relationship’ the right definition?
Ultimately, the Government’s goal is to protect those who need protection and allow those who don’t need this or actively choose not to want it, to opt-out of the system. A wider aim of the ‘Fairer end to relationships’ consultation is to support in reducing violence against women and girls (VAWG), a broad Government policy.
The concept of an enduring family relationship is certainly a relevant and helpful guideline, but it is absolutely essential that within this, legal professionals, the courts, and the public, are informed clearly about what criteria constitute this kind of relationship, and what couples and families will be given in return, but also the level of responsibility parties will carry as a result.
This relies on clear, plain-English set of rules that are structured, but not absolutely inflexible. It must also be made abundantly clear how people can opt-out of rights (should an automatic opt-in framework be introduced). Education is key, through school curriculums, media and professionals working with couples and families, such as conveyancers, financial advisers, estate agents and more.
Solicitors tip: Importantly, this consultation is only the very beginning. The closing date for responses is 14 th August 2026, and after this date the Government will review the feedback, and then there will be a formal Government response. However, reforms are potentially a long way off, so understanding your rights now is hugely important.
You can get in touch with our cohabitation lawyers now to understand your current rights.
Keep reading…
Should cohabitation law really be reformed?
What should couples talk about before moving in together?
What happens when unmarried couples separate? Considerations for cohabitees
