I’m kind of confused when reading your question. I am not sure what you mean by saying “I don’t hurt anyone.” Perhaps, you might think that by using pornography, you don’t hurt anyone physically, psychologically, socially, or spiritually? But, let me tell you my brother, if you take some time to think about this question seriously, I don’t think that you cannot recognize that you are hurting someone… and the very first person that you hurt is YOU. According to some studies, people who got hooked into pornography, often do poor in school, withdraw themselves from the society, do not want to pray nor to go to church nor to participate in any church’s activity; and from deep down of their consciences, they feel bad about themselves.
One more thing that you should keep in mind is the danger of using pornography. It tends to lead a person to sexual-related sins such as: masturbation, genital/oral sexual intercourse with other people.
With that, my brother, I think it’s wrong. It’s a grave offense. If you want to learn more what the Church says about this matter, read the Catechism of the Catholic Church #2354.