Can you PLEASE help me with family problems?

Six days ago I walked into my son's room and discovered him snorting what appeared to be cocaine. Before I could call my wife into the room, he threatened to show my wife "the video." I demanded to know what he was talking about, and he told me that he found a video me and my secretary made of us having . So now my son is addicted to drugs, my marriage is in jeopardy, and I'm being blackmailed by my own kid. What should I do??