Marriage on the decline: what the latest ONS statistics tell us about the ‘modern family’

The ONS’ (Office for National Statistics’) latest ‘families and households in the UK’ bulletin offers a valuable snapshot into how family life continues to evolve in England and Wales.  

It reveals three key trends:  

1. Marriage remains important but it’s no longer the sole (or even dominant) way in which families are formed. 

2. While no‑fault divorce was necessary and well received, it only addresses part of the family breakdown landscape. 

3. Cohabitation reform is required if the law is to reflect how families actually live (and subsequently separate). 

Here, Debbie Heald from our award-winning family law team delves deeper into the data, what it tells us about the ‘modern family’ and the steps that cohabiting couples should take to protect their rights. 

Marriage 

Married couples (either with or without children) account for 65.3% of all families in the UK, meaning that marriage remains the most common family structure. However, this marks a slow but consistent decline over the past decade, falling from 66.6% in 2015.  

For family lawyers, this confirms that while marriage is far from disappearing, it’s no longer the default family framework. It also provides a timely backdrop to some of the most significant developments in family law in recent years, such as no‑fault divorce and the renewed focus on cohabitation reform.  

The gradual decline in marriage forms the social context in which the Divorce, Dissolution and Separation Act 2020 came into force in April 2022, introducing no‑fault divorce. This significant and long-awaited reform removed the need to assign blame when applying for divorce. The move was designed to reflect that marriages now end by mutual decision and allows couples to collaboratively engage in forms of Non-Court Dispute Resolution to resolve financial and child arrangements.   

Yet while no-fault divorce modernised the resolution of marriage breakdown, it left the law of cohabitation unaltered. 

Non-married family breakdowns 

The most striking trend in the bulletin isn’t the decline in marriage but the growing proportion (34.7%) of family structures that sit outside of marriage. Alongside the decline in marriage comes the increase in these other family structures: cohabiting families (rising to 17.6%), lone‑parent families (rising to 16%) and civil partner families (rising to 1.1%) — all of which are grounded on commitment and financial interdependence.   

Despite the number of cohabiting families continuing to rise (to approximately 300,000 families), cohabiting partners still have no automatic financial rights against the other on separation — regardless of the length of the relationship or shared children. This means that in reality, family life has developed faster than the law. 

Cohabitation  

Family breakdown is now as much a cohabitation issue as a divorce one — even though the law continues to draw a sharp distinction between the two. Contrary to common opinion, there’s still no such thing as a ‘common law marriage’. No matter how long a cohabiting couple may have lived together or whether they have children, they don’t have the protection of the fairness‑based financial claims that are available on divorce. When relationships break down, disputes are often pushed into complex property or trust claims, with limited and unpredictable outcomes. 

Consequently, it’s likely that the 2025 ONS statistics will renew and reinforce the focus on cohabitation reform. In November 2025, the Government confirmed that it would consult on cohabitation reform and the financial remedies that are available on divorce, recognising that the two can’t be dealt with in isolation. A formal consultation is expected imminently (Spring 2026).  

How can cohabiting families protect themselves? 

The most effective protection comes from discussion, agreeing and planning ahead.  

It’s essential to: 

1. Seek legal advice as early as possible. 
2. Understand exactly how property is legally owned.
3. Discuss practicalities and intentions.
4. Enter into a cohabitation agreement, particularly if property is owned unequally or one partner is financially dependent.
5. Ensure that Wills, life cover and any death-in-service benefits reflect your intentions. Cohabiting partners don’t benefit from these under the intestacy rules.
6. Review your arrangements after any substantial life changes (such as the birth of a child). 

Understand your rights & seek expert advice 

The ONS data confirms what family lawyers see every day: more couples building lives, raising children and sharing homes without ever marrying. Yet under the current law of England and Wales, cohabiting partners still have no automatic financial rights when a relationship ends — no matter how long they’ve lived together. 

With Government consultation on cohabitation reform expected, the legal landscape may change. However, reform isn’t here yet and any future protections are unlikely to be retrospective.  

Until the law catches up with societal changes, the absence of marriage often means the absence of protection. Seeking legal advice before cohabiting and before a relationship breaks down isn’t pessimistic. It’s both sensible and practical. 

Our award-winning family law team — recognised in The Times Best Law Firms, The Legal 500 and Chambers and Partners — includes “lawyers at the very top of the profession”. 

Whatever your needs, talk to us by calling 0333 004 4488, emailing family@brabners.com or completing our contact form below.