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What is Adultery?

By Senior Associate, Family Law

The question ‘what is adultery?’ might seem to have an obvious answer, but in fact there are different understandings of this term and what it constitutes. To many people, adultery simply means the infidelity of a partner. However, this intuitive understanding doesn’t quite correlate with what the law in the UK says.

For the purposes of getting a divorce in the UK, adultery specifically refers to a married man having sexual intercourse with a woman other than his wife or a married woman having sexual intercourse with a man other than her husband. This means that many instances of behaviour that might at first seem to qualify as adultery aren’t seen like that in the eyes of the law.

Citing adultery as a reason for divorce

To obtain a divorce, you must be able to prove that your marriage has broken down irretrievably. You can do this by citing one of five different facts:

  • Adultery
  • Unreasonable behaviour
  • Two years separation with consent
  • Desertion
  • Five years separation

If your partner has been unfaithful to you and you want to apply for a divorce on the grounds of adultery, it’s important that you’ve a clear understanding of exactly what this means. As mentioned previously, in this country, you can only cite adultery as a reason for divorce if your partner has had sexual intercourse with a person of the opposite sex.

This means that if your partner has been unfaithful with someone of the same sex, technically they haven’t committed adultery and so you can’t give this as your reason for wanting a legal separation in your divorce petition. So whether you’re in a homosexual relationship and your partner has a same-sex extramarital affair or you’re in a heterosexual relationship and your spouse has cheated on you with someone of the same sex, you can’t rely on adultery as your justification for wanting a divorce.

It’s also important to be aware that adultery has to involve sexual intercourse. Even though many people assume that any kind of physical intimacy outside of a marriage would be seen as adultery, other types of sexual activity are not considered to fall into this category in the eyes of the law. For example, if you discover that your partner has been using dating websites, this does not qualify as adulterous behaviour. Even if your partner has been physically intimate with another person, it must be established that they had sexual intercourse for their behaviour to be deemed officially as adultery.

Another point to be aware of is that to be granted a divorce on the grounds of adultery, you must not have lived together as a couple for six months or more after you discovered that your partner had been unfaithful. If you do remain living together as a couple for six months or longer, you will forgo your right to give adultery as your reason for legal separation.

Is there another way to get a divorce if your partner has been unfaithful?

The narrow legal definition of adultery comes as a shock to many people who find that their partners have been unfaithful and who want to get a divorce. However, it’s important to bear in mind that there are other options aside from citing adultery.

Instead, you can cite ‘unreasonable behaviour’. This has a much broader definition and you can use it if your spouse has behaved in a way that you cannot reasonably be expected to live with. Inappropriate relationships with other people can - and frequently are - given as the justification for applying for a divorce.

You can take this approach if you’re in a same-sex marriage or if your partner has been unfaithful to you with someone of the sex same. You can also use this reason if you cannot cite adultery because you can’t establish that your husband or wife had sexual intercourse with someone else.

Hopes for change

The legal definition of adultery is increasingly outdated given the change in attitudes and laws the UK has seen over recent decades, particularly when it comes to same-sex relationships. This has led many to call for a change in the law to address the discrimination whereby same-sex relationships don’t constitute adultery. Highlighting the inconsistencies, despite the fact that gay couples have been able to enter into civil partnerships for approximately 10 years, it’s not possible to dissolve a civil partnership on the basis that one of the civil partners has committed adultery.


Many family lawyers also hope that divorce law in the UK will move towards a ‘no fault’ system. It’s believed that a more peaceful and less antagonistic approach to divorce is in the best interests of separating spouses, particularly where there are children involved.

A rise in cases of adultery on holiday

People start extramarital affairs in a whole range of situations, often with people they meet at work or through friends. Recently, there’s also been an increase in the number of people starting affairs online through dating apps and meet-up sites.

Interestingly though, at Slater and Gordon we’ve seen a rise in the number of clients coming to us citing their partner cheating on them whilst on holiday. To discover more about this, we commissioned a survey of over 2,000 married and divorced Brits. Our study suggested that one in 10 people have cheated on their partner while on holiday. Of these, 50% said their unfaithfulness was just a bit of ‘holiday fun’ and a chance to ‘let off steam’ while they were going through a difficult patch with their partner.

We also found that 37% of those who had committed adultery on holiday did so because they got carried away, while 34% said it was because they had consumed too much alcohol and 31% said it was due to relationship problems.

Regardless of why or when adultery occurs, it can have devastating consequences for relationships. If your partner has been unfaithful to you and you want to separate from them, it’s important that you’ve access to expert legal advice to help you through this difficult process.

How Slater and Gordon Lawyers can help you

At Slater and Gordon Lawyers, we understand the emotional strain that our clients are under when they need legal advice in situations like this. When you come to us for help and guidance, you’ll benefit from a highly personalised, compassionate and sensitive service. Our specialist family law solicitors will take the time to find out the full details of your case and advise you on the next steps. We’ll explain the different stages of the divorce process clearly and make sure you understand the legal terms you’re likely to come across.

You can rest assured you’re in safe hands with Slater and Gordon. We’ve the largest team of family lawyers in England and Wales and our solicitors draw on their considerable knowledge and experience to help you achieve the best possible outcome for you and your family.

We offer both fixed fee and flexible pricing divorce services and will enable you to get the results you’re looking for in the most cost-effective way.

Many of our family lawyers are members of Resolution, an organisation committed to resolving family law cases constructively, avoiding potentially long and costly court battles where possible. Most of our cases are settled through constructive negotiation, helping to keep costs and stress levels down for all parties.

If you’d like to discover more about our family law services and see how we can help you, don’t hesitate to call us on freephone 0808 175 8000. Alternatively, you can complete our online contact form and we’ll call at a time that suits you.

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