Like most red-blooded guys, I get turned on by some porn but ultimately porn is boring and unreal. I believe the attraction for 'porn addicts' is the variety and a form of jealousy. The desire to be in the situation but while remaining a detached voyeur. The real danger is not the porn itself but the isolation in this fantasy world that he is creating for himself.
I have a radical idea but you may not agree. You chould try being his porn star. Just put on a non-contact show for him and let him masturbate the way he wants. Its important for him to disengage from the computer and magazines and see a real woman for once. Once you have got his attention and he is satisfied the porn should be boring. It's important that you shouldn't feel that you're being used in this way - just that you fool him into thinking he's exploiting you. It's a big act.
Alternatively, pretend that you're really intested in his porn and masturbate him or yourself in front of the computer.
The whole idea is that you become part of his fantasies again and re-engage as people.

Alex.
(...but what do I know?)