I like thinking of it as a "ritual" rather than "addiction". Otherwise it feels very similar to what you are describing...a set intention made by a me that wanted a thing, and all I need to do is just stumble along the path now in progress.
@RussSharek Yes, it's clearly a ritual, and it sounds much better. I like how it implies that it has a personal meaning and a specific way to be done, while "addiction" is just something vaguely scientific and negative.
@RussSharek Yes, for me, it was really about setting myself temporal markers and stick to them until it became an automatism.
Now, I feel like I'm kind of addicted, but in a good way. It's funny to think that even on a bad day, when I'm not motivated at all to do my workout, I find myself already doing it anyway while still trying to find an excuse to not do it.