I understand your pain, really, I got Erectile disfunction too, there is a lot of factor to take in count.
First, it's true that masturbation may diminish your capacity to get hard. But relax, there is no need to beat yourself. Try to determine your trigger and try to change your habit.
Second, don't forget that in porn, actor are expected to take medication to stay hard, so porn isn't a accurate representation of the reality. Even "home made" aren't a good representation. Who really post bad intercourse, were are the fail, because there is a lot of fail and it's normal. It's life. My sexologist told me and my wife that sexuality is like a sky, sometime there is Sun, sometime there is cloud and sometime it's pouring rain, snow and ice (Condition may apply).
I like to say that, because it helped me a lot to release the pressure of having an intercourse like in porn. When I began with my girlfriend, I was really affraid of not being able to get hard. I was really stressful. It's normal, it's the first time. And I told her, and she was comprehensive. With time, I gain confidence, but it took months. Now, it's ok, but sometime, I get erectile problem, and we just do other thing.
So if it can help you, be yourself and give yourself the time to change.