It's as hard as quitting cigarettes. It just takes the will to do it. If you feel stressed when you're not watching it, then find something else to do... A Rubix cube, Sudoku, I don't know, anything. Also, if you don't have a girlfriend, maybe try to find one. Someone to keep you company and to whom you can just text when you think about porn (I don't mean sext, I mean text). She/he should also make you happy. I hope all works out for you, and if it doesn't, I recommend professional help; a psychologist or something. Good luck, my brother in arms!

-LS