Prone Masturbation or PIED, not sure

Hi everybody.

I'm currently 19 years old and I have masturbated prone for at least 10 years. I got into porn (the normal one, nothing weird) for at least 6 years. This has caused me to have problems with my erections when being with a girl, but even then I was able to achieve an erection sometimes.
The problem is, this year I learned about PMO, PIED and prone masturbation for the first time, and I became disgusted about it. I want to change for good. So I didn't watch it for 3 weeks, but I wanted to test if I had PIED or not, so I put on a video and I was hard in just 1 minute.
Recently (about 1 month and a half ago) I started talking with a girl, with which I'm currently having one of the best relationships I've ever had, and It's so meaningful to me. Anyway, I've noticed that, when being intimate with her, I seem to have a hard time having a proper erection, as I stand on the 40-50% range. I specially despise this, because I really like her, and I don't want her to think that she doesn't turn me on, which isn't true. But I'm sceptical about telling her this.

To conclude with, I don't know if I have the bad habit of prone masturbating, if I have PIED, or both. I feel lost
As of today, I'm on my second day of not watching porn and not masturbating (I tested myself for PIED last week even if I didn't masturbate, so I wanted to be honest with myself and started again). After this week, I will begin treatment to cure prone masturbation addiction. After 1 month, I expect to see better results and I will be able to tell if I really have PIED or if I'm just insecure with this girl, after all, it is the first time I'm being intimate with someone that I really like, and she really turns me on. Maybe I can cure PIED while treating prone masturbation, or maybe my only problem is prone M and I'm anxious about my performance all the time, which doesn't really happen with porn, because there you are alone and not with a partner.

Sorry for the wall of text, but I wanted to know what any of you guys think about this.

Any advice is of high value to me.

 

Thank you so much for the links. I've read them and I think that they are the most complete source of info I've read here.