@blackwind: "Just as long as no one is getting hurt or catching unnecessary feelings."
Which has, and still happens alot of the time considering the divorce rate in America. Since sex is pretty much a need, and make it or break it type of deal in relationships nowadays.. I wouldn't be surprised if getting hurt and unnecessary feelings are the cause.
These situations are probably caused by people who just feel horny and don't care about being emotionally or mentally ready for it.