Quote from the book Love and Murder in the Time of Covid by Qiu Xiaolong.

i am playing the guitar
i am being played by the guitar

Deciding to do anything deeply, one opens a path through which that very thing one wants to work with also works on us. It changes us physically–the mouth (armature) of a trumpet player or the callus on the finger of a string player are obvious examples–and it also changes us mentally. 

This is true for any relationship we have.