Is the 6-year-old daughter his child? If not I would be concerned about that...
One thing I remember hearing someone on a talk show recommend to one guy who was trying to overcome a porn addiction was to put family photos at places where he watched porn. For example, maybe put some photos next to the computer or around it. That way, instead of looking at the stuff he could remember how important his family is, how he didn't want to lose them and how disappointed they would be with him.
Honestly, I don't know if this would work. Especially if he doesn't believe this is a problem and doesn't want to change it.
I think if it were me, I would just ask him point blank questions. Let him know you know what he's doing. It's no secret (don't tell him how you know, just say you know). But ask why and what he "gets" from it. What are his feelings about it? I'd be trying to understand it. But then as far as "treating" it my guess is like any other addiction. I think what would help is if it's something he wants to change. For example, if someone wants to quit smoking they won't unless they truly want to do it and are willing to work at it.
You mentioned he drinks a bit too. Would you say he has other addictions besides porn?
There is no arriving, ever. It is all a continual becoming.
