I am not perfect in this matter, so keep in mind I am not holier-than-thou talking down to you.
After much thought, I strongly believe porn turns your thoughts away from your spouse and is essentially robbing her of all your admiration and love as you lust after something else, even if it is just a few minutes.
That’s wrong, and while it is very easy to rationalize it as not being sin, it is.
Just don’t see the problem (for most). Yes, this can ruin lives like many other bad habits.
I would argue that in moderation some forms of porn use can save marriages. It’s just a fact that many men have much stronger sex-drives than women. If you’re wife has sex with you once or twice a months because she’s not in the mood enough (tired, raising small kids, etc etc)What’s the guy supposed to do?
So he has a few sessions with rosy palm and her four sisters once in a while. Isn’t that better than having an affair with all the associated risks (diesease, pregnancy, divorce etc)?
Some people watch porn with their wives as a marital aide. Are they sinning too?
That might be the only thing saving the marriage. :)