I quit smoking cigarettes, and, despite the rhetoric, I wonder whether the two might be similar when it comes to dependency.
I used lozenges for about two weeks, and that seemed enough to break the habit of having cigarettes; the rest appeared to be willpower. My situation felt unique, yet I suspect yours could be equally powerful.
My fiancé, who was only 26 at the time and also smoked, had a stroke, and I estimate it was perhaps 99 % caused by, or at least catalyzed by, smoking (it was an ischemic stroke and nicotine is a vasoconstrictor). So, the thought in my head was, “if you continue to do this, you will die.”
With babies, they’re so fragile, and if you’re high something might happen and you might lack the wherewithal to react or take action. So, perhaps your mantra could be, “If I do this, I could end up harming this new life I am responsible for.”