Arya, first you have to realise that your problems with porn are more than an addiction. Most people masturbate, the majority look at porn, they do not have a big problem with it.
There are two reasons I can think of for wanting to stop, one is ED, which is a really practical reason, and doesn't necessarily require you to stop for ever, just cut down and go some long periods without, the other is psychological to do with how you relate to porn and masturbation and how it effects you. I would qualify that by saying that a significant proportion of men suffer severe anxiety from porn use, and this may be to do with their individual biochemistry of their brains that react to dopamine differently, for example they suffer greater come-down after orgasm.
You haven't mentioned suffering from ED, so I think the issue is the latter, how you relate to porn and masturbation both psychologically and biochemically.
You can start to explore the psychology here, but as others have said, it is probably wise to seek some sort of professional help. If like me, you are neurotic about porn use, a good therapist can help guide you out of the neurosis.
Opening up about my porn use was the best thing I could do, and it is still helping. I still feel repressed about discussing it with friends and family, but in some sense, it is still quite a taboo subject. Most men do it, but there is still a lot of desire for privacy and secrecy involved in the practice. Personally I just don't feel comfortable talking about it in person, though talking about it here has made me feel much more self-secure.
You are not alone. As I said, a significant minority of men who use porn and masturbate share your feelings. For them it really is destructive. Try to look at the positives, you say you have had relationships, that is more than me who has only had one that lasted six months. I'm sure there are other things in your life that are positive too.
Get to the root of your anxiety, understand it, it is not as simple as just dopamine release. Everything we do releases a small amount of dopamine as our brain assesses whether it wants to do it again or not. Dopamine is primarily for establishing repetitive behaviour, from cleaning our teeth to writing here.
Personally I think oxytocin, which is also released when you MO, is an equally important hormone to understand. It is responsible for emotional bonding, released when we give someone a hug or kiss for example, and so there is an issue about trying to bond with an artificial and non-responsive image.
I don't really understand the bio-chemistry of the come-down after MO, I'd like to know more about it, and this is definitely something to research, to understand why it makes you feel so worthless, but you can explore this issue from a psychological perspective.
Try forgiving yourself, you are not that abnormal, as I said, the majority of men use porn and masturbate, the issue is how you relate to it.
I look forward to hearing more posts from you.
Take care.
Thank you.
