Re: Here goes nothing... (sorry, very long)
At this point there is no more need for advice I do not think. as for any of BH, it all boils down to IF you can get over it, and in the long run do not count on just staying together for the kids will be the medicine that fixes it.
While never accepting her behavior, what anyone who stays MUST accept is that just like there is never a 100% guarantee it could never happen in the first place (we all thought differently) no matter what you do or do not do there is no guarantee it cannot happen again and I believe that that is the key issue you and all of us who stayed have to live with. No matter how much you work on the marriage, which is great, no matter how much therapy she or you get, it can happen again.
Some guys can live with that and some guys cannot and you should not set a specific time limit. Nothing wrong with what you are doing but I would not throw out the thought of a surprise polygraph at some point to make sure with your travel and him next door that her addiction does not occur again.
And if he moves not a great distance away I would not take that to mean you are totally in the clear. Her panic and fear now is because you actually have shown some real potential consequences. I hope you protect yourself.