Remember that addiction to something doesn't only mean you can't stop doing/eating/drinking it. Addiction also means using some substance or activity to avoid painful feelings when that substance or activity's primary purpose isn't the avoidance of pain. So even if you don't overeat, when you eat for comfort instead of hunger, you are eating addictively. This isn't necessarily a problem unless it is carried to extremes, e.g., gaining 100 lbs. or ONLY eating by yourself in front of the open refrigerator in the middle of the night.
Or, another example-- having a massage because it feels good and relieves stress seems a good match to me. Going to the mall and spending $500 on stuff you don't need because it feels good and relieves stress is addictive shopping. Again not necessarily a problem unless you do it every week and you can no longer step inside your house be cause it's so crowded with stuff-- AND in addition, other areas of your life are suffering.
So IMHO if someone is looking at porn in order to avoid intimacy with the partner, or escape into a sexual trance alone, that is addictive use of porn even if it only happens once in a while. I see nothing wrong with doing that **occasionally.** The problem is when the person chooses porn regularly instead of intimacy with their partner and at the same time they withhold intimacy from a willing partner because intimacy with a partner requires pushing outside their comfort zone.
