Sometimes one has to compromise a value for the good of what will be best served in the long run. Personally, I see you telling your W where you learned this could be devastating. Since you saw it on her computer at M-I-L's, that could damage the relationship between W and M-I-L.
Just a thought...
“Things turn out best for the people who make the best out of the way things turn out” ― Art Linkletter