Can he legally decide where I live?

by Jane
(Oregon)

Here's my child custody agreement question:

I live with my step-father, although my mother has legal custody. She is unstable, and so I choose to live with my step-father.

They're on and off again, but are currently broken up. They're still friends, and my step dad just got evicted, so did my mother, so we're moving.

I have no idea where yet. They haven't told me anything, all I can do is pack, but if my step-father moves out of town, then I know my real father will make me live at my friend's or grandmother's house, instead of living with my best friends in the town of my choice, even if my mother gives consent.

Is it legal for him to make me live where I don't want to?