The label "addict" does not have to mean "one who has done really bad stuff" - or at least "stuff worse than I have". It doesn't mean one has to actually voyeur, expose himself, or be oiver (transgress on) gilui arayos (ie. with another person - masturbation doesn't seem to 'count' for some reason ??) in order to really be "an addict".
As a matter of fact, I know of plenty folks who have been oiver on gilui arayos and are most likely not addicts. I doubt that the yidden in the midbar who were oiver with the shiksas at sheettim where addicts. I doubt that most men and women who have affairs are addicts - per some surveys, almost 30% of Americans have, and the idea that all of them are addicts is just plain silly, in my opinion. Of course, it may comfort us to point a finger and say "Oh, he's that horrible? He must be an addict."... but since when is being an addict an insult? Is it, do you think?
You may feel that, as yidden, we are held to a higher standard and maybe we qualify as "out of control" with less bad behavior than non-Jews. Perhaps masturbation is horrible enough... Rabbi Akiva may even tell us so (though he might feel the exact same shock about 150 other things we do nowadays). But I digress.
My point is, that I do not believe that "badness" is what defines how sick we are. I believe that it has very little to do with whether we are "addicts". Not being an expert on addiction, of course, all I can suggest is for you to read the First Step of the Big Book of AA. The realizations that brought us here, were:
1- that our formerly trusted and depended upon behavior (using lust, alcohol, gambling, heroin, whatever) actually makes our lives unmanageable - it screws up our lives and the lives of those around us, and...
2- that we came to the conclusion that we cannot successfully stop. We do not have to prove that we cannot stop (how do you prove something that hasn't happened yet?), rather, to me, it is just as Rav Noach zt"l would define beginner's Emunah/Belief in Hashem: "I have enough evidence to honestly accept that there really is a G-d." Then begins the lifelong mitzva of Yidias haBorei, yisborach Sh'mo.
In the same way, every recovering addict I know, has come to believe that he or she is an addict by weight of the evidence that they are not able to get better by their own power - after all, it was your/my very best thinking and efforts that got us exactly in this deep trouble, right? Wasn't it? If not, I suggest you just "try harder" and then we'll talk again.
So to sum up, the definition of "addict" is exactly these 2 things, per my own experience. The behavior may have been "mild" like schmutzy magazines or internet, masturbation, or more. It's not the behavior that matters - it's what it does to your life that is the issue, to me. The pivotal point here boils down to pure (enlightened) self-interest, not morality nor even Hashem's Will. This is plain to me, though others twist themselves into a religiomoralistic pretzel over it.
"Can I take it any more?" If I perceive that I can, and perhaps will be able to just stop tomorrow, then I will keep using my drug. Period. And that's what I call an addict. Like me.
So, what it all comes down to is either humility....or humiliation.
To sum up Dov's words: Once we have determined that (1) our former "friend" is making our lives unmanageable and that (2) we cannot stop on our own, we have the humility to admit we're addicts, and only then will we really reach out for the help we need to stop.