I'm not sure if this will help.... and of course my situation is completely different, but I haven't masturbated in years now, because I'm married, and I have found that it is much better to have sex in person than to masturbate. So when I may be tempted, I think, "No, as much as I am tempted, if I do this, I'm screwed with the wife for at least another week, so better to wait".
It's not that I have a stronger will than anybody, but I find this incentive to "reward myself, and my wife" by waiting it out, helps.
If, or at least when you have a girlfriend you could try to use that trick. If or when you don't, perhaps you could devise a "special night" with yourself. One that is perhaps involved enough that it would take a little more time and effort to set it up, therefore reducing the impulse to just do it.
Crazy idea maybe, but, we are not "normal" after all.