Couples sometimes take vows when they get married. We typically hear things like the marriage will be for better or worse, in sickness and health and until death do they part. However, 50% of marriages ultimately end in divorce or separation. The number one reason that we discovered during our research was infidelity. Couples argue, the economy has its ups and downs and all this places a strain on marital institutions, but nothing like infidelity. There are people married to spouses with substance abuse problems, and some are married to those with violent tendencies. These are issues that lead to divorce but not as often as infidelity. It may be possible to look past these indiscretions if you truly love someone. The reasons that people cheat are as varied as people are - from feeling neglected themselves, for feelings of inadequacy, or, they're just cheaters. People try counseling sometimes and others feel their ego has been too bruised to keep trying. Moreover, it can depend on whom the spouse cheated with.