Adultery is still grounds for divorce in the UK and a crime in many countries around the world. Back in 2012, there were speculations that gay marriage would spell the end for adultery. This has not come about. Both LGBT activists and family lawyers have argued that the law should go, while courts have been resistant to what they see as trivial procedural change. But far from obsolete and archaic, the legacy of the adultery law still resonates powerfully in how we think about love, sex and divorce.

Onerous origins

The English church began to prosecute people for sex acts in the 12th century. Adultery was criminalised in the sexual morality codes alongside sodomy, which back then encompassed all kinds of transgressive sex. Church advice was so thorough as to warn against deviant positions like the woman going on top, oral sex and sex ‘a tergo’, from behind, which perhaps excepting anal sex, was seen as the most sinful position of all. Their approach was rather more comprehensive than current divorce law which defines adultery exclusively as straight, penetrative, consensual sex, leading to a bizarre situation when in a country proud to have legalised gay marriage, there is no such thing as gay adultery.

Given the public’s wanton disregard for ecclesiastical counsel, adultery became so common that by the later Middle Ages it was not even considered grounds for the dissolution of marriage. By the 19th century this had all changed. Adulterers were punished in the divorce courts where adultery was the key prerequisite for dissolving marriage. Proceedings would degenerate into public shaming in open courts. All the salacious details that entertained and scandalised the nation made social pariahs of the divorcees. In spite of this, court records show what may have been cases of staged adultery – a farce famously depicted in Evelyn Waugh’s A Handful of Dust. These masquerades would see a wife would burst in at a pre-arranged time with a detective and photographer. Modesty often dictated that both husband and lover would be found on the bed fully dressed, from top hat to shoes, when they were surprised in flagrante. This kind of evidence would later be dismissed as collusive. Just as today if you don’t petition for divorce within six months of discovering the adultery the court will declare you to have ‘condoned’ it, you have to be sufficiently aggrieved and disobliging for your spouse’s cheating to count as adultery.

The adulterer’s blame game

In real terms adultery is no longer punished in the divorce courts. A guilty spouse who wants to remarry quickly might be somewhat more willing to agree to a favourable settlement. However adultery no longer affects legal decisions about financial matters or children. Most courts would also recognise that adultery can be symptomatic rather than the cause of a failing marriage. What adultery law does do is maintain a blame-based divorce system which can compounds issues in already unamicable break-ups.

The hopeful Family Law Act of 1996 attempted to veer away from ascribing blame in divorce proceedings. However the outdated, conduct-based system still ensures fault-based divorce. If a couple wants to divorce without the time delay of separation or desertion, their only other option is claiming their partner has acted unreasonably.  The procedural blame-game forces the partners into a corner. If it is the naughty spouse who wants the divorce this can amount to: “you can either divorce me on the grounds of my adultery or I will divorce you on the grounds of your unreasonable behaviour.”

Criminal convictions

Though our own system condemns the intrusion and all-too-frequent abuse to women’s rights that comes from criminalising adultery, British nationals are still affected by adultery laws worldwide.

In 2008 a young British man named David Scott was charged and thrown in a Filipino jail after moving to live with his long-term girlfriend Cynthia Delfino, whose separation from her estranged husband was not complete.  In 2009, Marnie Pearce was jailed for three months after being accused of having an affair by her Egyptian husband, later that year the same happened to Sally Antia, the wife of a British airline pilot, after her husband reported her infidelity to the police.

Though all European countries have decriminalised adultery, in Obst v Germany [2010], the European Court of Human Rights upheld the Mormon Church’s dismissal of its European PR Director as a result of his sexual indiscretion.

These prosecutions are somewhat at odds with a public comprised of 1.2 million Ashley Madison users at the time of the infamous breach. Indeed barely a third of British people now think an extra-marital affair would put their relationship under strain, an official study suggests.

Unwelcome and outdated

Today we have longer lives, more lovers, and the hegemony of the holy, mother Church is somewhat diminished, but the seventh commandment continues to entrench itself in legal dressing. Adultery jars with how sex and divorce proceedings should be dealt with in modern marriage and to eradicate it would disaffiliate our own law from systems that criminalise adultery. Until then however, the spectre of medieval morality codes loom large.