I had a very eyeopening experience that taught me how evil some people can be.
I was in my mid-40's and very unhappily married. I worked for a fairly large law firm that had grown rapidly and thus we were spread out between two offices 2 miles apart. I was having a bad day and a legal assistant in the other office called me about a file. I didn't know her very well but I knew she was married, early 30's and stunningly attractive. I vented about my day, one thing lead to another and before long she was meeting me for sex and telling me she loved me. What I didn't know is that she was fucking around with a lot of other guys. She was a topic of conversation in her building and she was complaining to her supervisor about everyone talking about her. A secretary in my building who was trying to look out for me told me that another attorney, "Joe", who worked in the other building, had told her that they were sleeping together. I didn't believe it and I sent her an email that said "word over here is that you're fooling around with Joe. She took my email to her boss to prove what people were saying about her. I knew nothing until the Senior Partner showed up in my office and, without giving any specifics, said that the woman had reported that I had sexually harassed her. She didn't want any action taken against me but wanted to report it. I denied everything to the senior partner and refused to believe it - after all, we were planning in meeting up after work to hook up in 2 hours. The Senior Partner insisted it was true and that he wasn't going to do anything and to just watch what I say to her. I went to my immediate boss - thinking I was being framed - and he told me that it was about the email.
I called her but she wasn't answering - she was with Joe. When she finally answered, she had a convoluted explanation she was trying to make up which made no sense. I couldn't believe a woman I was actively sleeping with could make a complaint against me just to stop being the subject of office gossip. Ironically, word spread fast and there were people who knew her husband and she was afraid she'd lose custody of her kids and she quit.
The incident cost me in some intangible ways and was quite embarrassing.