ED because of insecurity and overthinking

I’ve been having erection problems ever since I’ve been having sex with girls, which is about 15 years now. Which is longer than my porn problem, which only started a bit later. Now, this doesn’t mean they’re not related at all, but there is another cause for my ED that I wanted to talk about here: insecurity and overthinking.

Ever since the very first time I was with a girl and we were about to have sex, I have had this voice in my head: what if I can’t do this? And that voice becomes the only thing in my head, my growing erection quickly goes away and that is the end of that. This has happened SO often: I think at least half of the times I was in a position to have sex, I ruined it in this way.

Now, as I said, watching porn definitely doesn’t help, especially since I have now come to realise that even though porn is not the cause of my insecurity it definitely sustains it. But I wanted to ask if anybody has some good advice what to do with the undermining thoughts: you’re in the moment and a voice comes up saying you’re gonna lose your erection. How do you make it go away and stay focused?