Analysis of more than 5m divorce cases by Co-operative Legal Services has shown that bad behaviour has overtaken adultery for the first time. The study compared the grounds for divorce in the forty years from the 70s to the present day.. It found that while in the 70s, 29% of marriages ended because of adultery, the latest figures show only 15% of divorces were due to infidelity. In the 70s unreasonable behaviour was cited in 28% of cases but it now accounts for almost half of all divorces (47%). Christina Blacklaws, director of policy at Co-operative Legal Services, said: “Although society’s attitudes to divorce have changed, with less of a stigma attached to it, the grounds for divorce have remained enshrined in law for decades.” She said the widely held belief was that divorces were granted because of unreasonable male behaviour, “but there has been a marked shift over the decades, with men now five times more likely than in the 70s to be granted a divorce because of the unreasonable actions of wives”.