Analysis of more than 5m divorce cases has shown that claims of unreasonable behaviour have rocketed, the study revealed.
Co-operative Legal Services compared the grounds for divorce in the 70s, 80s, 90s and 2000s as well as the present day.
It found that while in the 70s, 29 percent of marriages ended because of adultery, the latest figures show only 15 percent of divorces were down to infidelity.
In the 70s unreasonable behaviour was cited in 28 percent of cases but it now accounts for almost half of all divorces (47 percent).
Examples of unreasonable behaviour given to lawyers for divorce 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 - 40,000 pounds - and burning it in the bedroom.