First, your husband and all his idiot “friends” are going to lose their jobs if they continue using work computers to look at and trade porn. Ask your husband if the pleasure he gets is worth losing his ability to support his family?
Second, disconnect the home computer. I am serious. Yes, I know we all use them for a lot of things, but you can still get paper bills, write checks, and mail them. Cancel or suspend the ISP, disconnect everything, and put all the equipment in a corner of the garage. Do this while he is at work one day, so he finds it like that. When he asks why, tell him you are taking away his smut supply because you refuse to live with that in your house.
Third, insist he get counseling, either at church or from a reliable professional who deals with sex addiction. Because even if he is not an addict yet, he is on his way. Porn is so pervasive and destructive to a psyche… In college I watched some and thought for the most part that after a while, it’s just boring and gross. However, my roommate and her boyfriend got into the nastiest magazines and trading porn on the internet. After a while, it was all they did. She lost her ROTC scholarship and had to drop out of school, and they just looked at the grossest things together. She showed me some of it one time, and I realized just how far and how fast a person can go from seemingly normal naked people pix into bestiality, anatomically impossible-looking contortions, and group/orgy stuff. Just because you have to keep the variety or the effect wears off.
Make this a big deal, because I really believe you are fighting for your husband’s soul, his ability to have a normal sexual relationship, and your marriage. Not to get too personal…but has this affected your sex life yet? Is he neglecting you in favor of the pictures? That happens very often…pix don’t demand anything of you or make you vulnerable.