I have been in your position bro.
The first problem was, we dont believe that we could actually beat this thing. We want to beat ofcourse but we doubt if that truly happens.
Second problem was, even if belief was there, its scary to be without all the pleasures that PMO would bring. So we feel that we are missing out soon after we start nofap, hence relapse.
Third, with belief as well as desire, we need bullet proof reason to quit. Why because…
We are more dangerous when we got nothing to loose.
Example, look at cigarette smokers ( I was that years ago, and was sober for 5 years, I consider myself a non-smoker now and not as someone that quit) they know its wrong, most of them want to quit, they know all the health issues that follows with it, but guess when most of them quit? When their health is actually in trouble. Then somehow their confidence level rises to beat the addiction… Same issue here, we dont think that its our worst situation yet. But trust me bro, you dont want that worst situation. But again, thats how our mentalities are… We keep trying only to fail again and again. Trying to convince ourselves we are trying, failing for our pleasure.
So change the approach bro, change the motivations behind it, change the reasons, look for things to do when urges hit ( plan it before - liking going to a war with weapons), find the way to feel that this time is the worst case scenario ( like do or die scenario and make sure you do)… Prepare for what ever happens scenario, Because without that, its hard to quit, and by whatever happens, I mean " what ever happens, I am quitting this thing, doesn’t matter the urges, think of the worst thing that could happen (both physical, emotional or others actions), and tell yourself, even if that happens, i wont relapse, that way you are preparing to make sure no excuse will make you relapse"
On top of that, make sure there is fire in you every single day to keep going. One day if you skip or not on your best self, relapse happens. So things has to be concrete in every direction.
Good luck bro 
