Hi Yahweh,
There's stuff online you can read that explains it better than I do. Just google it. Here are some quick links though that I like:
http://www.covenanteyes.com/2015/02/27/porn-cause-erectile-dysfunction/
http://www.mensjournal.com/health-fitness/health/are-you-watching-too-much-porn-20130821
Some members swear up and down it isn't real because they've never experienced it or masturbated up to 15 times a day because of compulsive masturbation, but I'm sure they know best. There was another member here who experienced it as well named Skynight, you could probably search his old posts for more anecdotal stuff.
To be fair, I have a host of other neuroses that together create a perfect storm, which I won't rehash. Some of my older posts under the name Klingsor are still here and you can search those if desired. I'm probably a limiting case, an asymptote. It's unlikely most guys would make it to the same point I did simply because it's unlikely that they have as many comorbid influences.
Regarding porn, if you let it take control it can become an addiction as bad or worse than any narcotic. Especially if you are unable to be intimate with real people. However, some argue that it provides an acceptable outlet for sexual frustration for introverts and losers like me who can't get the real thing. Nevertheless, I was masturbating to fantasies and summer clothing magazines long before I had access to porn, so I doubt it makes any difference in that sense, and this is why I often say it's a force for the worse.