I know it seems counter-intuitive, but in my experience, focusing on the specifics of the addictive behavior is really not productive in treating the addiction. By that I mean that it doesn't matter too much what type of pornography he has used, or even that his addiction is pornography. The physical and chemical brain changes in addicts are very similar whether the addiction is alcohol, gambling, exercise, pornography, food, whatever. It doesn't mean porn itself is evil or morally wrong (although I do think it's often damaging for people who are in sexual relationships). It only means some of us can't use it in a healthy, moderate way.
In your boyfriend's case, several key addictive components are present: 1) His need to intensify or escalate the behavior to get the same "rush", 2) His return to the behavior in spite of his desire to stop, and 3) Negative consequences for personal relationships and other parts of his life. Those are really important for determining whether something is an addiction. Healthy activities enhance your life and relationships, they don't damage it.
Using myself as an example, I'm confident I'm not an alcoholic. I know this because I can have one beer after work and then have no more. I can go a week without drinking, no problem. My drinking of beer has not negatively affected my life. But that's not the case with pornography. Once I start looking at pornography, I can't stop on my own. I used it in spite of the horrible effects on my relationships, and risking jobs. That's why I'm seeing a therapist and working a 12-Step program.
Your boyfriend's addiction is not about you, or your body, or your behavior, or anything you're doing or not doing. The addiction is about him. If he wants to change he'll need to take those steps on his own, for himself. The only action you need to take is to decide whether you want to stick with him while he battles this disease.
Recovering sex and pornography addict
The magic of asking for help is not in the help, but in the asking.