But I say to you, that whosoever shall look on a woman to lust after her, has already committed adultery with her in his heart.
Ego autem dico vobis : quia omnis qui viderit mulierem ad concupiscendum eam, jam mœchatus est eam in corde suo.
Matthew 5:28
Pornography is one of the modern world's marriage destroyers, yet very few people today make the effort to stay away from it. As Jesus says, if you look lustfully at a woman, you've already committed adultery with her in your heart.
Jason Evert in the YouTube clip talks about the destructive effects of pornography on a marriage. He asks how marriage can last if a man is constantly comparing the images he sees in pornography with his wife, and how he can be satisfied with her body if he's been trained to become bored with women's bodies in 15 to 30 seconds. Very few marriages can survive infidelity and pornography is a means of being unfaithful, no matter how people rationalise it.
If you are shocked by this whole concept of pornography being harmful to a marriage and you want to stop your addiction, never fear, recovery is possible. Have a look at this link: Breaking free of pornography.