First talk honestly to the husband directly as to why the spouse might feel the need to do this,(i.e. is there a distress in the married life or is it simply a taiva or a simple slide in frumkeit)
Why jump to embarrass the husband in front of the family Rov? He will be embarrassed enough as it is.
After confronting the issue the husband and wife should set up a filter. If for some reason a filter cant be had on the computer, let the spouse know for the time being you will monitor computer usage.
An essential part of this is for the husband to learn a mussar sefer 15 minutes a day (plenty are available with a good English translation) and husband and wife together should read a book on Shalom Bayis.
If the husband says this has nothing to do with the wife and is simply a taiva and hard struggle that he cant defeat on his own have him promise to speak to a well known Rav or marriage counselor that you can mutually agree upon within a short set time frame. If he fails to follow through, then speak to a Rav/counselor and make the appt.for him. You are out to help the marriage and come out stronger not to embarrass the husband.
Unnecessarily, disclosing this info to your Rav can do irreparable harm. The relationship of a husband with a Rav is very important and might make him feel ill at ease when needing support and asking halachic shailos and might even force him to switch shules.
B)Keep in mind this can be attributed to a reaction to outside stress the husband is just keeping inside,and actually happy with his relationship with his wife,and might actually need help with that stressor and the improper internet usage is a symptom resulting from that .
c) As Rabbi Reisman said by the Flatbush internet asifa, that while it is an aveira, looking at improper things on line does not mean that you need a get from your husband or that he is a rasha.
D) I assume your friend made sure that there were not teenage boys that could have been on the internet at that time.
Wishing only simchas