I'm new to these forums and am not sure who I'm replying to but this goes out to the wife.
I'm not a professional but I would suggest confronting him as directly as possible. Tell him you love him and that he needs to stop going on pornography because he is married and it goes against God's will, tell him you know he is going on pornography (if he denies it) and if he really loves you and if he really is a christian he will acknowledge he needs to stop.
Offer him help to stop, perhaps offer something more in the bedroom, something he fantasizes about (unless of course it's also sinful) and take control of things so he stops. If he uses the internet to view it remind him that God says it's better to cut off your hand then to let it cause you to sin, now I don't suggest he cuts of his hand but getting rid of the internet certainly applies here!
The internet isn't a necessity humans have lived without it for a few thousand years! It may be a sacrifice for the family but without the internet it will be harder for him to be tempted and to sin. If he needs the internet for work then find another way for him to use it. A public internet cafe would insure he can't view pornography but if work needs something more private then use strict internet rules and programs. He can only use it around other people for instance not in a private study room and use programs which email you what sites have been visited.
I can only hope this helps, if he really is a christian with his whole heart he will know it's wrong, if he doesn't then he is just using god's name as a get a way card.