Last year, according to a recent study, 56 percent of business professionals admitted to having had a relationship with a coworker. When workplace relationships don’t work out (and even when they do) employers often must manage a welter of negative workplace effects—from potential sexual harassment claims to the appearance of favoritism, and from retaliation claims to conflicts of interest. So what should an employer do to avoid the potential fallout from office relationships—and how can companies avoid Valentine’s Day disasters?