Questions about porn usage

Feel free to skip to the end if you don't want a mini backstory and just want to help me answer my question. However, paragraph 2 will offer some insight into other factors.

Alright, so I feel my motivations for this website have shifted a lot. I started out doing nofap 2 years ago to get a t-level boost, did what I needed to, and am more than happy with my hyper-masculinity. I switched to doing it for the dopamine detox, due to a mental breakdown around day 30 of my streak I relapsed hard and couldn't recover my streak until the past few months (two 30+ day streaks). My motivation at the time was to cure my premature ejaculation and get some of my old motivation back (I am an overachiever). Then things got interesting sometime last week. I tried to masturbate without porn as a means of trying to improve my premature ejaculation last week, only to realize I couldn't get a proper erection (I am 18). I grow and don't show, so when I get a failed erection... it scares me.

I was going through a process of temporary separation with my current ex (I say current because of unique circumstances that will bring us back together eventually) girlfriend, but I did not plan on using porn for my masturbation. Until erectile dysfunction hit, then I went for it. Basically, once I decided I would try and train myself to last longer using porn instead of just my brain (likely a dopamine issue) I still had a solid inch of my penis not there. I am usually around 6.25-6.5 (that is where I was at the age of 16), but now it's about 5.75 and has gone down further the past 2 months (was 6 inches 7 weeks ago, before my streak of 50+ days). Obviously, I will be needing some sort of medication to fix that erectile dysfunction issue, so I won't be asking for advice on that. My question is related to porn usage. I have a burning will for accomplishing life goals, I enjoy going outside instead of using the internet, I don't get any enjoyment from social media, I even hate porn... like I have no interest in it anymore... it's disgusting, yet I want to use it as a tool. A tool to slow down my premature ejaculation. I have conditioned myself to cum within 10 seconds sometimes, and that is something I need to fix.

My motivation for fixing it is my ex-girlfriend, obviously, and this period of pause is actually of benefit for me trying to accomplish this goal. I feel a servant's mindset when it comes to sex. I hardly want it for myself, don't worry about my own pleasure, focus on the other person. I am still a virgin, but I know this is what I will be wanting from it. I want her to enjoy herself, I need her to. I can't do that 100% with premature ejaculation. She said it isn't an issue, because I am the first she's met who wants to not focus on their own pleasure (she has no idea that I don't care for my own pleasure, she only knows I am going to focus on her's), but that isn't enough for me. I want to give her everything I can.

So, now that you're down here, I will simplify this. Is using porn to get a near 100% erection for training premature ejaculation a bad idea? Again, my motivation and dopamine isn't an issue.