Office extramarital affairs could start innocently through friendship or great chemistry at work. People at work experience the same pressures, hardships, they have common goals and they even celebrate their victories together.
Wives sometimes tell me that their husband truly is never going to care because he has checked out of the marriage. I find that even in those cases, there is still regret. Most people realize that regardless of the state of your relationship or the circumstances, there are options other than cheating.