There doesn't even have to be a hierarchy, how about that?
Many of us practice egalitarian polyamory, where no one is primary, secondary, or tertiary at all -- and all partners are considered just as important as any other.
That being said, being submissive has nothing to do with being considered "secondary" or not.
The world opens up... when you do.
Oh, oh, can't you see? Love is the drug for me. ~Bryan Ferry
"Love is that condition in which another person's happiness is essential to your own." ~Robert Heinlein