Erection Problem

Hi all, first I will state I am new here and this is my first post. I didn't know where else to go with this issue and it is difficult to talk about with anyone around me, so here I am. I am a 26 year old male

As the title states I am having erection problems. Not all times just in situations with girls.

I suppose it started with my first ever girlfriend the first time i got intimate with a girl. We had been dating for about 6 months and decided to lose our virginity's and to stop being nervous. But everytime we tried, I had trouble getting an erection. This went on for another couple months until the relationship eventually ended.

Since this I have been with around 8 woman and I would say with at least 6 of them, this issue has arisen. My concern everytime is that there is something wrong with me. It has driven me to not avoid relations with women but to be nervous right from the beginning of the relationship, about that moment in the bedroom where things are starting to go that way, and in that moment those worries are intensed to the point I almost want to shut it down because im so nervous the problem is going to happen again and i don't want to ruin another relationship. The most recent event this happened was with a girl I was really starting to like and the same situation happened, no erection. She was nice about it and said it happens and didn't make me feel judged about it, but immediately starting being very distant and uninterested, eventually leading to the end with her, which has made old feelings resurface of something being wrong with me and thinking I have some sort of erectile dysfunction, which is upsetting me to almost intolerable levels.

This being said, there have been a few situations where I have been able to reach erection and perform but not being able to do it most times worries me. I should also note that alone with a porno video playing I am able to achieve an erection without even touching, just watching.

My hope coming here is I can get some advice and some help to figure out what is wrong. I just want to be happy and not feel so nervous the entire time I start hanging out with someone new. In striving to fix this I have undertaken the 90 day no PMO challenge and am currently on day 3, though I only watched porn 3 days a week max since i was 15.

I hope to hear some advice, thanks.