Well, not jacking of to Girlfriendporn is actually a good sign. You have not distanced yourself from reality as much as liking the porn more than the actual thing - regarding your girlfriend.
In order to understand our addiction we have to focus on the details: What is our goal? away from porn. Porn film? porn pics? magazines? fantasy? what is the addiction you have?
There is the focus you should aim on. If you have the feeling that you can watch porn like a movie I personally think this is not the right way. Your brain is receiving sexual stimuli and you do not fulfill the urge your body has although the brain tells you to. This could rewire you the wrong way. Don't get me wrong here, keep the Pron of you and your girlfriend. But remember: Withdrawl is always more difficult if the substance is in sight. Porn is something different however since you don't introduce the drug externally. If you have the feeling, internet porn is not a danger to you anymore and you can handle it, then you can of course use porn with yourself to satisfy your needs. I however suggest you satisfy your needs by doing the actual thing. This eventually is our goal I think.