He will not have many wives.

I started the wonderful series of lessons on Mitzvot kekekht niht, and there you raise a question that the first and last generations discussed, whether to refer to the reason and not to be turned away in the halakhic ruling regarding not multiplying wives. On the one hand, we can say that if he multiplies righteous wives, then it is permissible because his heart has not turned away, and there is the Maimonides who says that one should not change the boundary because if you changed the boundary, you necessarily did not achieve the reason. I wonder if the following division cannot be proposed (similar perhaps to what you wrote about the mitzvot of result regarding fruit and multiplying):
There is how I fulfill the commandment.
And there is the metric/result by which I determine whether I have achieved it or not.
So here we can say that if my heart is turned away – I have violated the prohibition.
But the way to observe the prohibition is not to multiply wives.
And it makes more sense to me if they reduce the reason (something I haven't heard of anyone doing) to "so that a woman won't take away my heart."
I would love to know what you think.