The harmful effects of pornography/Watching porn can't be described in words.But I try to write some major effects of it.
1.First of all it harms your sexual ability.It caused so much damage on your sex.
2.You didn't get satisfaction doing sex with your wife if you are porn addicted.
3.It causes many more diseases related on sex.Also decreases power to prevent other diseases.
4.You can't so much active on any work.Get so much angry by normal things.Nothing can be very interested to you.
5.It harms your brain,could not solve hard problems,decreases your creativity also,can't memorize something easily.
6.Day by day sexual crime is increased like rape for this addiction.
7.The person who watch porn regularly have a higher tolerance for abnormal sexuality, including rape,sexual aggression,promiscuity.
8.The interest of good family relation loss by it.
These are only some effects.You can search to know many more about it.You hardly believe it.