New and confused, advice welcome

[touchdown]

My wife and I have been married for 20 years and we have a teenage son. We both work in the travel industry and work opposite days so that someone can be home for our son. In a very short time frame my wife has shown the classic symptoms of a "run away wife". First the sex stopped, then the volcano erupted, then the wall went up not allowing me to change, or let me inside her life. I now get the "I am not sexually attracted to you therefore how can I have sex with you". She is using every thing I have done wrong in the past to justify her actions. She now has told me that we need to separate and she is looking for an apartment. I told her that I am not leaving that this is her issue. This all happened in a very short period of time. I am devastated. I had no idea this could happen so fast. I have tried to talk her out of leaving for my son’s sake and try to work things out. He will be devastated. She wants out! She told me that her heart says give me another chance, but her head says run. She does not know how to get the passion or the sexually attractiveness back. This seems to bother her most. I have made an appointment with a recommended MC. This is going to take 4 weeks to get in an appointment. I have found this website and ordered DR. It cannot come fast enough. Today was a common day off for both of us, and it was a disaster. She broke down in a crying panic (nervous breakdown type) saying I can’t take this anymore. I need to move out. I am just starting to understand, I think, what she is going through. What can I do? What do you recommend? I understand the DR book is for me only. What about the “The Marriage Breakthrough® Interactive Seminar on DVD” for both of us. Any advice would be greatly appreciated. This has happen so fast I am scrambling for answers. Someone please point me in the right direction. I have already made some mistakes that I have learned by reading these boards

Thanks in advance