The reason to turn off the porn might become, to thoughtful people, not a moral one but, in a way, a physical- and emotional-health one; you might want to rethink your constant access to porn in the same way that, if you want to be an athlete, you rethink your smoking. The evidence is in: Greater supply of the stimulant equals diminished capacity.
After all, pornography works in the most basic of ways on the brain: It is Pavlovian. An orgasm is one of the biggest reinforcers imaginable. If you associate orgasm with your wife, a kiss, a scent, a body, that is what, over time, will turn you on; if you open your focus to an endless stream of ever-more-transgressive images of cybersex slaves, that is what it will take to turn you on. The ubiquity of sexual images does not free eros but dilutes it.
Of course, the Christian can not escape the moral implications and soul-destroying power of pornography.