Making a habit of masturbating at porn and finding more and more exciting videos as the old ones tend to bring less and less arousal causes sexual desensitization over a long period of time. This is because the brain gets used to your own ways of reaching climax (i.e. porn & masturbation) so you will become less impressed by real women - they are now too vanilla for you compared to what you have experienced via porn.
It is somehow like drugs. First it brings you virtual joy and then, over years, it gives you real pain because being unable to perform with real women can be devastating for a man's psyche.
So please stop masturbating at porn for good. Try real women instead. You need to separate yourself mentally from your past porn experiences. So think positively and don't look back. Go chase real women and forget about porn.
Depending of your age and of how deep you are into porn, your recovery may take between several weeks and more than a year, I think.