Pornography is not primarily a behavior issue; it is a worship issue. Porn and other sexual sins (sin in general) are issues of idolatry, so when we talk about the root of an addiction, we must begin with our makeup at conception and say, each of ourselves, “I was born worshipping.” The question then becomes, “What do I worship?” and the consequence, “Will I acknowledge and repent of my idolatry?”
Harold Best gives us an idea of what it means to worship, “I have worked out a definition for worship that I believe covers every possible human condition. It is this: Worship is the continuous outpouring of all that I am, all that I do and all that I can ever become in light of a chosen or choosing god.” 
In relation to pornography, then, sex becomes a god, an idol that we would pour ourselves into as, functionally, we trust its pleasurable end above and beyond God’s promise to satisfy. 
It seems to me that we do not fully acknowledge or understand the weight of our sin as eternal treason against a God who describes himself as jealous for our worship. While at one time pornography was so taboo that it could not be mentioned aloud, now we talk about it as though the normalcy of the struggle somehow justifies returning to its snares. Or, returning to its snares every so often and comparing the amount of failures I’ve had to the amount of failures he’s had like, “Well, I’m doing okay.” 
We can’t say that the root issue of pornography is its instantaneous availability. The root is not internet access. We can’t say that the root issue of pornography is a lack of accountability. 
The root is idolatry. We must first begin with the fact that we either worship the Creator or idolize the created. 
It is not that we are born with the option to worship, but that we are born worshipping, and are transformed into the likeness of the objects of our worship. The Psalmist described this: “Their idols are silver and gold, the work of human hands. They have mouths, but do not speak; eyes, but do not see. They have ears, but do not hear; noses, but do not smell. They have hand, but do not feel; feet, but do not walk; and they do not make a sound in their throat. Those who make them become like them; so do all who trust in them” (Ps 115:4-8 ESV). In the same way, pornography begins to shape the lens through which our eyes see (or don’t see) created image-bearers of God, the mind through which we filter (or don’t filter) those images, the mouth through which we speak of those objects, as the overflow of our hearts are spilled out with all of their black-tar contents. 

“What people revere, they resemble, either for ruin or restoration.” – G.K. Beale


But there is a seed to the root – an even deeper root than worshipping sex or creation. The seed of those things is pride. It is pride that says we know what will please us better than God knows how his creation works. It is that same pride that Satan, the father of lies, whose deceit is old as the ages, turned to as described in Isaiah 14:13-14: “You said in your heart, ‘I will ascend to heaven; above the stars of God I will set my throne on high; I will sit on the mount of assembly in the far reaches of the north; I will ascend above the heights of the clouds; I will make myself like the Most High.'”
There is a lie parading about that says holiness is as simple as: “Do this, and don’t do that. Don’t be bad, be good.” I am convinced it is one of Satan’s most destructive tactics. It is opposite the freely given, gospel vaccine we need to reverse our worship distortions. All it does is add another idol for us to pursue – goodness – when we’re busy trying to avoid badness. 
I had some sort of epiphany recently where I realized that just because the visible blossom – the budding flower – of sin (in this case, pornography) has withered away does not mean that it’s root has been, well, uprooted. If you can think of sin as a plant in four parts – seed, root, stem and flower – you see that cutting off the colorful top isn’t the same as uprooting the problem. It is a humbling realization that as soon as you’ve gotten rid of “the big sins” you have their roots to deal with, and the roots are often more difficult to acknowledge once you’ve just gotten to feeling good about yourself after having broken the stem. 
What hope is there if we are all idolaters? “He will crush your head, and you will strike his heel” (Gen 3:15b). From the moment after the fall of man when humankind began to worship the created, the Creator implemented his plan to crush our idols and reconcile us to himself through Jesus Christ. 
The wages of our idolatry lead to death, and we need the preexisting Word, the eternal Son of God, to defeat it. He does.
We attack the root issue at the cross of Christ. Repent, and rejoice. Christ’s death, burial and resurrection is the hope we have for the death of sin – seed, root, stem and flower – and the rising to new life in Jesus. 
“Since, then, you have been raised with Christ, set your hearts on things above, where Christ is, seated at the right hand of God. Set your minds of things above, not on earthly things. For you died, and your life is now hidden with Christ in God. When Christ, who is your life, appears, then you also with appear with him in glory. Put to death, therefore, whatever belongs to your earthly nature: sexual immorality, impurity, lust, evil desires and greed, which is idolatry… Let the peace of Christ rule in your hearts, since as members of one body you were called to peace. And be thankful. Let the message of Christ dwell among you richly as you teach and admonish one another with all wisdom through psalms, hymns, and songs from the Spirit, singing to God with gratitude in your hearts.” – Colossians 3:1-5;15-16
Jesus loves you enough to attack your roots, no matter how painful the uprooting may be. May he be your strength in the fight. May he be your all in all.