Commitment° is a choice
If you don't think about it, you might think commitment is something external to you: that it sort of happens by itself (once you're in a relationship long enough, once you work somewhere long enough, etc).
It is a choice (though you might not want to choose too early). The "intuitive" version of commitment, i.e. the externally mediated one, changes smoothly over time, like a sigmoid. But you can override this by choice: saying "as of today, I commit to X, not Y". Then it's more like a step function than a sigmoid.
Often these are done ritually, to make it Legible to everyone else too: Marriage, bar mitzvah, etc.