Pornography has only one purpose: self gratification. Porn makes all other people into mere objects which are used to gratify the self. This is why porn will destroy a marital relationship. The person using porn lives in a fantasy world inhabited by perfect people who are there only to satisfy his (or her) needs and desires, no matter how perverted. No one in the real world can live up to the fantasy standards of pornography, and as a result, often the user of porn will no longer be able to relate to his or her spouse. This is also why porn so often leads to rape, child abuse, etc. Porn destroys the idea of a relationship. To the porn addict, other people are just a drug to be used however you wish to get your fix.
Pornography not only destroys the ability to form true, loving relationships with other people. It also robs the porn addict of the ability to elevate his or her thinking to a higher spiritual level and enter into a relationship with God. The main concern in life is for sexual, physical gratification, and anything that does not lead to that is pretty much rejected.