Not that I much experience yet, but I know the first time my H left back in June, I tried going to the best friend he went to stay with, to get answers and to "get him to find out what was wrong etc etc, talk sense into him" all that pathetic chasting stuff. Biggest mistake I ever made.
I know you haven't consciously or deliberately gone through the friend but it won't make a difference to your W.
Stand strong Mac and keep going with making Mac the most amazing guy on earth. The Mac that your W can't stay away from.