Matthias Media puts out a periodical called The Briefing. Matthias is an evangelical ministry based out of Australia. It is nice to read articles with an international flavor. A couple of years ago they put out an entire issue devoted to the topic of purity. Here is an excerpt from an article written by James Warren called, "The Naked Truth About Porn." Warren points out what we know but can too easily forget: pornography is destructive at every level!
Long-term, not only does pornography deaden attraction for one's partner, it deadens the ability to have healthy relationships in general. All people are increasingly objectified for what they can do sexually for the voyeur. Porn distorts all relationships, and prevents the growth of loving other-person-centered relationships.
Here are some resources on the topic that may be of help:
Especially for the married:
Sex, Romance, and the Glory of God by C. J. Mahaney
Sex and the Supremacy of Christ, edited by John Piper and Justin Taylor
God on Sex: The Creator's Ideas about Love, Intimacy, and Marriage
For everyone:
Pure Sex by Tony Payne and Phillip Jensen
Not Even a Hint: Guarding Your Heart Against Lust by Joshua Harris
The Purity Principle by Randy Alcorn