In This Post

In this definitive guide you’ll learn all about the grounds of divorce in the UK. 


  • What are the 5 grounds of divorce?
  • What constitutes ‘unreasonable behaviour’?
  • How can I prove adultery?
  • And more…

Let’s dive in...

What Are The Grounds For Divorce?

This complete guide explains all the legal grounds of divorce in the UK. People are sometimes surprised to learn that you cannot divorce simply because you feel like it. In law, you need to show that the relationship has ‘irretrievably broken down’. This means that your marriage is completely broken, and cannot be fixed.

To show that the relationship has <bloglink>‘irretrievably broken down’<bloglink> the person who applies for the divorce (called ‘the Petitioner’) must prove one of the 5 grounds of divorce:

  • Adultery
  • Unreasonable behaviour
  • 2 years separation (with consent)
  • 5 years separation (without consent)
  • Desertion
grounds for divorce

Additionally, you need to have been married for at least a year before you can apply for a divorce and get your <bloglink>decree nisi and decree absolute.<bloglink>

(However, you might be able to separate within the first year of your marriage if you're eligible to <bloglink>annul your marriage<bloglink>)

With that said, let’s check out the 5 grounds of divorce.

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The grounds of adultery forms the basis for about 20% of divorces in England and Wales.

To use adultery as the grounds of your divorce, you must:

  1. Prove that your husband or wife had sexual intercourse with someone else, and;
  2. File for divorce within 6 months of finding out about the adultery.
A woman in a red dress waits for her date to arrive

Proving Adultery Happened

Adultery is one of the faster ways to get a divorce, as unlike 3 of the other grounds, there is no minimum time that must have passed before you can file for divorce.

However, it is difficult to prove.

<bloglink>Adultery<bloglink> has a specific meaning in law- it must be actual sex (not just general ‘cheating’ or ‘heavy petting’).

So you need proof that your spouse slept with someone else.

And obviously, people tend to keep their infidelity hidden!

So circumstantial evidence, like pictures of them going into a hotel together, is unlikely to be enough.

Mobile phone or social media evidence, like a text message where your spouse admits they slept with someone, could be enough. But be very careful in how you obtain such evidence. Accessing someone’s phone or social media without consent, or using hidden cameras, could amount to harassment.

In reality, many couples agree to get divorced after an infidelity is discovered, and the unfaithful party simply admits in writing to the adultery as part of the divorce petition.

Filing For Divorce Within 6 Months Of Discovering The Adultery

You must also file for divorce within 6 months of discovering the adultery (ie. not when the adultery actually happened, but when you found out about it).

This is because the infidelity must make it intolerable for you to live with your spouse anymore. The courts tend to think that if you continue to stay together for more than 6 months after you learned about the adultery, then you no longer find it ‘intolerable’ to live with them.

A hand holds a watch with a leather strap
You must file for divorce within 6 months of discovering the adultery.

If you’ve waited more than 6 months, or you cannot prove adultery, you can still use infidelity or an affair under the alternative ground of unreasonable behaviour (which we'll look at next).

But before we do, a few additional points to note about the grounds of adultery:

  • Adultery only applies if it was your spouse who slept with someone else (ie. you cannot file for divorce on the grounds of your own adultery).

  • Your spouse needs to have slept with someone of the opposite sex (ie adultery does not apply in same-sex relationships).
  • There is no requirement to name the co-respondent in your divorce petition (ie. the person your spouse slept with). In fact, it’s a good idea not to, as it can needlessly complicate matters.

Unreasonable Behaviour

Unreasonable behaviour is the most common reason for divorce, and is used in about 45% of all cases.

It is the top reason for divorce in the UK because:

  1. It is relatively easy to prove.
  1. You do not have to wait for a set period of time before filing for divorce (which you do with several of the other grounds).
  1. You can use fairly mild allegations, meaning your spouse is less likely to object.

To divorce on the grounds of unreasonable behaviour, you must show that your spouse has acted in such a way that you cannot reasonably be expected to live with them any longer.

Broken crockery lies on the floor after a heated argument

To do this, you have to make specific allegations against your spouse.

This can range from serious allegations to very mild or vague allegations, for example:

More serious allegations

  • Physical violence
  • Coercive or controlling behaviour
  • Infidelity (of any kind)
  • Verbal abuse, such as insults or threats
  • Drunkenness or drug-taking
  • Social isolation or financial control
  • Breach of an occupation order
  • Breach of a prohibited steps order

Less serious allegations

  • Being bad with money
  • Lack of a physical relationship
  • Not sharing responsibility for the home, finances, or childcare
  • Frequent arguments
  • Emotional distancing
  • Vague issues such as ‘lack of support’

There is no definitive list of reasons, and if the allegations are serious (like violence), you may only need one or two examples. If they are milder (like working too long, or not tidying the house), you may need five or six examples. Domestic abuse can also be given as one of the reasons for exemption from the <bloglink>mediation information and assessment meeting.<bloglink>

In reality, the courts set a very low bar, and most couples can find something they dislike about their partner that can amount to ‘unreasonable behaviour’.

In fact, it’s often a good idea to try and agree on the allegations first. This makes the divorce more amicable and quicker, as your spouse is not contesting the allegations.  If you are on good terms, you may be able do this between yourselves. If not, a solicitor can draft the allegations for you.

A couple of key points about unreasonable behaviour:

  • You cannot use your own behaviour (it must be your spouse’s behaviour).
  • You must file for divorce within 6 months of the last act of unreasonable behaviour (if you continue to live with your partner without any more problems for 6 months, the courts are unlikely to find that the relationship has ‘irretrievably broken down’).

Living Apart For 2 Years (With Agreement)

This ground for divorce does what it says on the tin.

You must have:

  1. Lived apart for 2 years, and;
  1. Agreed with your spouse that you both want to get divorced.

The main reason people choose not to use this ground is that you have to wait two years before you can divorce and move on. Many people instead choose the quicker route and use unreasonable behaviour as the grounds for divorce.

A man packs boxes as he gets ready to move out

A point to note- while you must have ‘lived apart’ for 2 years, this doesn’t actually mean you have to live in separate households.

You can continue to live under the same roof (perhaps for financial or <bloglink>childcare reasons<bloglink>), as long as you live a separate life to your spouse for the 2 years. This means you do not socialise together or live a shared life. However, you have to prove to the court that you lived separate lives for 2 years, despite being in the same house. This can be hard to do, so many couples instead use unreasonable behaviour as the grounds for divorce.

Living Apart For 5 Years (Without Agreement)

Again, this grounds of divorce is fairly self-explanatory. You simply need to have lived apart for 5 years.

However, in this case, you don’t need the agreement of your spouse, and you can get divorced even if they don't want to.

This ground of divorce is often used when your spouse has left and simply disappears for good.

However, before the court will award a divorce on these grounds you must first make every reasonable attempt to serve your spouse with the divorce petition.

So, you’ll need their address.

If you don’t have their address, you can apply to the court for alternative service, such as sending the divorce petition to your spouse’s work address, or to a member of their family, or even via social media.

Once you’ve proved to the court that you have served your spouse with the divorce petition, or made every reasonable attempt to do so, they will allow you to <bloglink>apply for the decree nisi<bloglink> and formalise your divorce.

The main downside of this grounds of divorce is the amount of time it takes. Five years is a long time to wait before being able to remarry or move on.

Top Tip:

There’s an old myth that you become ‘automatically’ divorced after a long separation (say 5 years apart).

This is not true.

Even if 5 years have passed, you still need to apply to the court and issue a divorce petition.

An icon of a lightbulb


This ground applies when your partner leaves, and intends to desert the marriage (ie. never come back)

After they’ve gone for 2 years, you can apply for divorce.

This is quicker than waiting for 5 years (as above), however, these grounds of divorce are very rarely used. This is because you have to prove your spouse intends to desert you (rather than merely having left). This can be very hard to do, and so usually an alternative grounds is used.

Will The Grounds Of Divorce Affect My Financial Settlement?

People often think the grounds of divorce can affect the <bloglink>divorce settlement.<bloglink>

For example, they believe that the party who committed adultery should get less in the financial settlement.

However, rightly or wrongly, this is generally not the case.

People often don’t realise that the divorce process (getting divorced) and the divorce settlement (dividing your finances) are two distinct elements.

Infographic- the divorce process vs the divorce settlement

The courts separate the reasons for the divorce from the financial settlement, and the grounds for divorce are usually irrelevant to the final award.

To learn more about the factors the court does take into account when dividing the finances, check out my divorce settlement guide.

Note: if you have a <bloglink>prenuptial agreement<bloglink>, that will dictate the terms of your divorce settlement.

The Divorce Process

The overwhelming majority of divorces are undefended, meaning both partners agree to get divorced. That’s why most divorces are either based on the grounds of unreasonable behaviour, 2 year’s separation with agreement, or adultery.

5 years separation and desertion do not require your spouse to agree to divorce, but either take a lot longer or are hard to prove.

Either way, once the grounds of divorce are established, you can apply for divorce and the respondent can submit their <bloglink>reply.<bloglink>

If you agree to divorce, and matters are very straightforward, you may be able to do this yourselves online. But in anything other than the most simple cases, you will likely need a lawyer. You can find out more about the costs of online divorce, and using a lawyer in my special guide:

The Grounds For Ending A Civil Partnership

The grounds for ending a civil partnership are:

  • Unreasonable behaviour
  • Living apart for more than 2 years (with agreement)
  • Living apart for more than 5 years (without agreement)
  • Desertion

They work in exactly the same way as for divorce.

A couple enter a civil partnership

The main difference is that adultery is not a grounds for ending a civil partnership. The reason for this is that, as discussed, the definition of adultery under English law does not include same-sex infidelity (mostly for historic reasons), and when the Civil Partnership Act was passed it was intended for same-sex couples (although now heterosexual couples can also enter a civil partnership).  

If there was infidelity in a same-sex relationship, this can still be used as an example under the unreasonable behaviour grounds.

In any case, most of these quirks within the law will become irrelevant when divorce law changes on the 6th of April 2022.

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No Fault Divorce

On the 6th of April 2022 the new <bloglink>"Divorce, Dissolution and Separation Act 2020"<bloglink> will become law.

This is a huge overhaul of divorce law in England and Wales.

It is intended to reflect changing societal attitudes by recognising that people can want to get divorced without it becoming a ‘blame game’.

Under the new law, you simply need to provide a statement saying the relationship has ‘irretrievably broken down’.

There will be no longer be a requirement to prove any of the grounds of divorce discussed above, making the process much simpler and quicker.

Divorce Grounds FAQs

Is domestic violence a grounds for divorce?

No. Domestic violence is not a grounds for divorce by itself, but it can be used as an example of ‘unreasonable behaviour’. Due to the serious nature of domestic violence, it’s likely you would only need to show one or two examples in order to establish unreasonable behaviour.

What is the difference between abandonment and desertion?

Nothing. Abandonment is simply what they call it in the US. In the UK, we say desertion.

Are ‘Irreconcilable differences’ one of the divorce grounds?

No. It is a commonly used term when couples drift apart, but is not a grounds for divorce. You could cover ‘irreconcilable differences’ within the unreasonable behaviour grounds, by giving some very mild examples of behaviour, such as not spending enough time together.

Paying For A Divorce

A common problem for couples is drafting the grounds of divorce and any allegations. This is very difficult for most people, and you should really have a lawyer help you.

However, many people worry about how they will pay for the costs of a divorce lawyer.

Well, you can now get assistance from specialist funders who can help pay for your lawyer's fees up-front.

You can use this specialist funding for:

  • Mediations sessions
  • Solicitor led negotiations
  • Going to divorce court
  • And more...

Specialist funding is rapidly becoming one of the most convenient and cost-effective ways to fund your divorce.

Check out my divorce funding page to learn more.

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Neil Johnstone is a barrister and the founder of Neil is a barrister with an interest in all forms of civil and family law, and has appeared at all Court levels, up to and including the Court of Appeal.

Neil started this site in response to a common problem he noticed: Clients were unable to pursue deserving cases due to a lack of up-front funds. Neil knew that better access to No-Win-No-Fee representation and legal funding could help bridge the gap, and so founded; a unique comparison site connecting clients, law firms, and specialist funders.

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