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. Keep in touch! Check out HuffPost Divorce on Facebook and Twitter.