My married boss Jim had four young children when a recently hired 18 yr old came to work in our office, her name was Marta.  It was pretty clear he started having an affair with her as she was never given any work to do, she sat at her desk looking pretty and reading magazines and going through her personal mail all day.  Months later, something happened and Jim was transferred up from Orange County to San Fransisco.  We all learned his wife was filing for divorce.  Not long after Jim went to San Fransico Marta also left for the same location.  I guess Jim ended up dumping her leaving her to raise the twins she ended up having by him.

Office romances can end up well, but clearly Jim took advantage of a very young girl and basically ruined not only her life, her childrens lives, his wife's life, his childrens lives and for sure his life.

Me personally, I've had many crushes on men I have worked with but I never let them know.  It was enough for me just loving to go to work and seeing them.