The article below gets into great detail on what happens with pornography and the brain. There is also a link to a free e-book:

http://www.churchleaders.com/pastors/pastor-articles/173331-luke-gilkerson-bods-the-bible-and-the-brain-the-truth-about-porn-addiction.html?utm_source=newsletter&utm_medium=email&utm_campaign=clnewsletter&utm_content=CL+Daily+20140320

Along similar lines, this next article is written by Dr. Al Mohler regarding an article that J.R.R. Tolkien wrote to his son about sex and purity.

http://www.albertmohler.com/2014/03/11/from-father-to-son-j-r-r-tolkien-on-sex/

Have a good day in the Lord!