Infidelity is to blame for fewer divorces today than it was in the past, according to new research by Co-operative Legal Services, a U.K.-based company.

The researchers looked at over 5 million U.K. divorce cases beginning in the 1970s and found that people today are half as likely to list cheating as the reason for their marriage breakdown.

Their research indicated that in the 70s, 29 percent of divorces were caused by infidelity, while today only 15 percent of divorcing couples blame their breakup on an affair. Modern couples are much more likely to cite unreasonable behavior as the cause of their splits; 47 percent of divorcés today cite unreasonable behavior, compared to 28 percent in the '70s.

According to The Guardian, some examples of unreasonable behavior include "an unsociable husband making his wife feel guilty when she wanted to go out with her friends, a cross-dressing husband who decided to have a sex change, and a spouse withdrawing all the family savings."

This isn't the first study to look at rationales for divorce. Research from August 2013 found that parents are more likely to divorce after their kids' summer vacations, and a recent study out of Kansas State University found that couples who argue about finances, particularly early in their partnerships, face a greater risk of divorce.

Click through the slideshow below to see even more fascinating divorce research.

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  • Couples Who Share Housework Are More Likely To Divorce

    Splitting chores could lead to divorce? According to a Norwegian study released in August 2012, the divorce rate among couples who divvy up household chores is <a href="http://www.huffingtonpost.com/2012/09/28/divorce-rates-couples-who_n_1923623.html">roughly 50 percent higher </a>than for those in which the wife handles the housework. So does that mean couples shouldn't split the chores equally? Not necessarily. Researchers say that the higher divorce rate has more to do with "modern" values and attitudes -- such as viewing marriage as less sacred -- rather than a <a href="http://www.huffingtonpost.com/2012/09/28/divorce-rates-couples-who_n_1923623.html" target="_hplink">cause-and-effect relationship</a>.

  • Divorce Could Be In A Woman's Genes

    In February 2012, Swedish scientists released a study suggesting that a specific <a href="http://www.huffingtonpost.com/2012/02/27/karolinska-institute-divorce-gene_n_1304899.html">gene may explain why some women have a hard time committing</a>, or staying committed, should they marry. The researchers found that women who possessed a variation of the oxytocin receptor gene known as A-allele were <a href="http://www.huffingtonpost.com/2012/02/27/karolinska-institute-divorce-gene_n_1304899.html">less likely to get married</a> due to difficulty bonding with other people. Those with the gene who did marry were 50 percent more likely to report "marital crisis or threat of divorce."

  • A Close Relationship With Your In-Laws May Change Your Divorce Odds

    In November 2012, a 26-year longitudinal study released by the University of Michigan found that when a husband reported having a close relationship with his wife's parents, the couple's risk of <a href="http://www.huffingtonpost.com/2012/11/27/in-laws-and-marriage_n_2199637.html">divorce decreased by 20 percent</a>. On the other hand, when a wife reported having a close relationship with her husband's parents, the couple's <a href="http://www.huffingtonpost.com/2012/11/27/in-laws-and-marriage_n_2199637.html">risk of divorce <em>increased </em>by 20 percent</a>. Why the difference? Researcher <a href="http://online.wsj.com/article/SB10001424127887323713104578137222992767676.html">Terry Orbuch told the Wall Street Journal</a> that she believes that many wives eventually view their in-laws' input as meddlesome, while husbands tend to take their in-laws' actions less personally.

  • Men Are More Likely Than Women To Turn To Drinking After A Split

    A University of Cincinnati study <a href="http://abcnews.go.com/blogs/health/2012/08/20/marriage-means-more-drinking-for-women-less-for-men/">presented in August 2012</a> found that<a href="http://www.huffingtonpost.com/2012/08/20/drinking-after-divorce_n_1812235.html"> men are more likely than women to turn to drinking</a> after divorce. "Marriage and divorce have different consequences for men's and women's alcohol use,"<a href="http://consumer.healthday.com/Article.asp?AID=667788&loc=interstitialskip"> study author Corinne Reczek told Health Day.</a> "For men, it's tempered by being married and exacerbated by being divorced." Additionally, the study suggested that <a href="http://www.eurekalert.org/pub_releases/2012-08/asa-set_1081312.php">married women drink more</a> than their divorced or widowed friends -- partly because they lived with men who had higher levels of alcohol use.

  • Cold Feet Warn Of Marital Trouble Ahead

    Don't ignore those pre-wedding jitters: they may warn of marital trouble ahead, according to a <a href="http://www.huffingtonpost.com/justin-lavner/do-cold-feet-warn-of-mari_b_1910770.html">UCLA study published in the Journal of Family Psychology</a> in September 2012. Researchers asked 232 newlyweds in their first marriages whether they had <a href="http://www.huffingtonpost.com/justin-lavner/do-cold-feet-warn-of-mari_b_1910770.html">"ever been uncertain or hesitant about getting married"</a> after they got engaged. The research team followed up with the couples every six months for the first four years of their marriages. In a <a href="http://www.huffingtonpost.com/justin-lavner/do-cold-feet-warn-of-mari_b_1910770.html">HuffPost blog</a>, one of the researchers, Justin Lavner, explained that premarital doubts predicted divorce rates four years later, especially when the doubtful partner was the wife. <a href="http://www.huffingtonpost.com/justin-lavner/do-cold-feet-warn-of-mari_b_1910770.html">According to Lavner,</a> "19 percent of couples in which wives had doubts were divorced four years later, but only 8 percent of couples in which wives did not have doubts ended up divorced. Husbands' doubts did not significantly predict divorce, although divorce rates were somewhat higher among husbands with doubts (14 percent) than husbands without doubts (9 percent)."

  • Men Who Cheat Are More Likely To Have Heart Attacks

    According to a study released in May 2012 by the University of Florence, “sudden coital death” is more common when a <a href="http://www.huffingtonpost.com/2012/05/23/cheating-study_n_1540465.html">man is engaging in extramarital sex </a>in an unfamiliar setting than when he's having sex with his spouse at home. The researchers found that infidelity outside the home was associated with <a href="http://www.huffingtonpost.com/2012/05/23/cheating-study_n_1540465.html">"a higher risk of major cardiovascular event,"</a> including fatal heart attacks. “Extra-martial sex may be hazardous and stressful because the lover is often younger than the primary partner and probably sex occurs more often following excessive drinking and/or eating," researcher <a href="http://www.dailymail.co.uk/health/article-2148426/Its-just-bad-marriage-Cheating-partner-heart-attack.html">Dr. Alessandra Fisher told the Daily Mail</a>. “It is possible that a secret sexual encounter in an unfamiliar setting may significantly increase blood pressure and heart rate, leading to increased oxygen demand.”

  • Moving In Before Marriage No Longer Predicts Divorce

    Living together before marriage is <a href="http://www.huffingtonpost.com/2012/03/22/movein-before-marriage-no_n_1372687.html">no longer a strong predictor of divorce</a>, according to a study released by the Centers for Disease Control and Prevention in early 2012. As part of a marriage survey of 22,000 men and women, researchers found that those who were engaged and living together before the wedding were <a href="http://www.huffingtonpost.com/2012/03/22/movein-before-marriage-no_n_1372687.html">about as likely to have marriages that lasted</a> 15 years as couples who hadn't cohabited. What about couples who moved in together but weren't engaged? The study found their <a href="http://www.huffingtonpost.com/2012/03/22/movein-before-marriage-no_n_1372687.html">marriages were less likely to survive</a> to the 10- and 15-year mark.

  • Divorce Is Too Expensive For The Poorest Americans

    More couples are opting for long-term marital separations because they <a href="http://www.huffingtonpost.com/2012/08/20/divorce-expensive-americans_n_1811821.html">cannot afford to divorce</a>, according to a study conducted by <a href="http://www.huffingtonpost.com/2012/08/20/divorce-expensive-americans_n_1811821.html">Ohio State University</a> that was published in August 2012. Researchers surveyed 7,272 people between 1979 and 2008. Most people in the study who separated from a spouse reported getting a divorce within three years of separating. But <a href="http://www.eurekalert.org/pub_releases/2012-08/asa-msa081412.php">15 percent of people who separated did not get a divorce within the first 10 years</a> because it was too costly, especially when children were involved.

  • Divorce Hurts Health More At Earlier Ages

    Divorce at a <a href="http://www.huffingtonpost.com/2012/01/30/divorce-study_n_1242553.html">younger age hurts people’s health</a> more than divorce later in life, according to a <a href="http://msutoday.msu.edu/news/2012/divorce-hurts-health-more-at-earlier-ages/">Michigan State University study</a> released in January 2012. Sociologist Hui "Cathy" Liu looked at self-reported health information of <a href="http://msutoday.msu.edu/news/2012/divorce-hurts-health-more-at-earlier-ages/">1,282 participants over the last 15 years</a>, analyzing the difference in well-being between those who remained married over the course of the study and those who divorced. Among the divorced, Liu found that those who split at a younger age <a href="http://msutoday.msu.edu/news/2012/divorce-hurts-health-more-at-earlier-ages/">tended to have more health issues</a> than those who divorced later in life. Liu said the findings suggested <a href="http://msutoday.msu.edu/news/2012/divorce-hurts-health-more-at-earlier-ages/">older people have more coping skills</a> to deal with the stress of divorce.

  • Women Close To Divorcing Tend To Work More Hours

    In November 2012, the European Economic Review released a study that revealed <a href="http://www.dailymail.co.uk/sciencetech/article-2232318/Is-wife-working-late-It-sign-marriage-trouble.html">women who clock an extra 12 minutes per week face a 1 percent increase</a> in the risk of a marital breakdown. Why? Lead researcher Berkay Ozcan, PhD, explained that working more hours is <a href="http://www.dailymail.co.uk/sciencetech/article-2232318/Is-wife-working-late-It-sign-marriage-trouble.html" target="_hplink">a "form of insurance"</a> for women when their marriage is on the rocks. The study also found that there is <a href="http://www.dailymail.co.uk/sciencetech/article-2232318/Is-wife-working-late-It-sign-marriage-trouble.html" target="_hplink">no strong evidence</a> to suggest men do the same when divorce seems likely.

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