The Grass Is Greener? Adultery and Divorce

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In Autumn 2017, series 2 of Dr Foster gripped the nation.  The magnificent Suranne Jones was back, playing the betrayed wife, Dr Gemma Foster.  Her and her ex-husband Simon, played by Bertie Carvel demonstrated how devastating adultery can destroy a marriage and the lives of everyone involved.  Who can forget those powerful lines: “There’s only one way I’m leaving here and that’s in a coffin,” smirks Simon.  “That’s good to know” replies Gemma.

Few things are as devastating as finding out your spouse has been having an affair.  And although you think such a thing could never happen to you, it is estimated that a whopping 50-60% of married men and 45-55% of married women engage in extramarital sex at some time or another during their marriage[1].

Although these figures are sobering, they should come as no surprise.  Only 3 -5% of around the 5,000 species of mammals (of which humans are one) mate for life[2].   In the past, when marriages were little more than financial transactions, monogamy was only important for women.  Men were free to sow their wild oats wherever they fancied.  But we should not feel too bad for our ancestral sisters; in 1800, if they survived childhood, the average life expectancy for men was around 40 years.  Therefore, if a woman lived long enough, she did not have to put up with an unfaithful husband for long.

In today’s world, we marry for love, companionship and to provide a safe environment to bring up children.  Adultery is viewed as unacceptable by most people and is a reason to divorce a spouse in the UK.

The grounds for divorce

The only ground for divorce in England and Wales is that a marriage has irretrievably broken down for one of the following reasons:

  • adultery
  • unreasonable behaviour
  • desertion of two years
  • separation of two years (both parties must consent to the divorce)
  • separation of five years (no consent is required)

Adultery and unreasonable behaviour are the most common reasons cited for causing the relationship to break down irretrievably.

For adultery to be considered a reason for divorce, the petitioner (the person filing for divorce) must prove that because of their spouse’s unfaithfulness they find them intolerable to live with.

What is classed as adultery under English law?

In the context of a petition for divorce, adultery is the voluntary sexual intercourse between a man and a woman who are not married to each other but at least one of whom is a married person.  Sexual intercourse requires at least partial penetration by the male of the female. Attempts to commit adultery do not amount to adultery, but may be pleaded as unreasonable behaviour in the context of an ‘improper association’.

In general, the fact that the petitioner finds it intolerable to live with their spouse if they have committed adultery is generally not questioned, unless the respondent decides to defend the divorce (which is extremely rare).

Living together after adultery is discovered

If you have discovered your spouse has committed adultery and continued to live with them for six months or more, you will be unable to use adultery as a reason for the marriage having irretrievably broken down.  For example, in the case of Kim v Morris[3], the wife obtained a decree nisi (a document stating the court can find no reason for the divorce not to proceed).  However, she and her husband reconciled for four years before the divorce was finalised.  When they finally decided to part for good, it was held that under the Matrimonial Causes Act 1973, section 2(1) there is a complete bar on the court being able to grant a decree absolute (the document which ends the marriage) if the parties have cohabitated for six months or more after the discovery of adultery by one of the spouses.

The court will disregard periods of less than six months, should you and your spouse be forced to live together whilst sorting out new living arrangements.  If the affair has been long-running, time does not begin to run until after the last act of adultery has been committed.

Proving adultery

If the respondent to the divorce petition signs the acknowledgement of service personally and answers yes to the question ‘Do you admit to the adultery alleged in the petition?’, the court will accept that as sufficient proof of the alleged adultery.  Due to the expense involved in trying to prove adultery, it is best to have the respondent accept the reason and have them sign a confession statement.

In the rare cases that the respondent defends the divorce and adultery must be proved, an opportunity to commit adultery is not enough for the court to reach a conclusion that it was committed.  The petitioner will need to show, on the balance of probabilities, that the respondent also had the inclination and desire to be unfaithful.

Final words

If you are contemplating a divorce, you will need the advice and support of an experienced family solicitor.  Knowing that your spouse has been unfaithful is undoubtedly harrowing, but by getting expert legal advice, you can move on with your life and have a bright, post-divorce future.

Bennett Griffin is an award-winning solicitors based in West Sussex with offices in central Worthing and Ferring.  Our experienced and specialist solicitors offer a comprehensive service and will work with you in an honest, considered, and practical manner.  Our family law and residential property department can advise and assist you in relation to obtaining a divorce.  Please contact us on 01903 229 999 or by email at for more information.

The information contained in this article is for general guidance only and is not intended to be legal advice. Professional advice should always be taken on the application of the law in any particular situation.



[3] [2012] All ER (D) 108 (Jul), [2012] EWHC 1103 (Fam)