One definition of addiction is: compulsive, repeating behavior, despite definite resulting harm to one's own body and/or self-worth, work, family, other relationships, etc.
I've been with some pretty big-chested women. I still mourn my personal "one who got away." (God, she was huge.) I've also had girlfriends who are almost flat.
I guess, to me, big tits are a form of pleasure, like watching TV or movies; I can imagine being a character in the movie, but I recognize that I have a different reality. I'm not that hero detective in that TV show, I'm not a Starfleet officer -- but for a little time I can forget who I am and immerse myself in the story. Same with breasts. It's a hobby, perhaps. Some collect stamps or coins or comics and debate their quality -- "mint," "very good" or otherwise? We similarly collect images of large-breasted women and apply critical standards. I never really thought about it before.
For me, it's therefore a hobby. In real life I value love over tits. I'm sure we all do -- but that if we can ever get both together, well that's the best!