Not so sure about it being a modern phenomenon. However, it is a good thing that we are taking a look at it. Modern life with the computers and internet for sure are creating some serious social dysfunctions.
The entire situation is exacerbated by the use of sex as an agent of advertising. The VA has yet to get a handle on it with the soldiers returning from Iraq and Afghanistan where the troops are relatively isolated from the population. However, it is a big but big problem.
Do travel through the link and take a look for yourself. Sex addiction: The truth about a modern phenomenon