For me, each relationship I have is unique. Trying to measure them on some sort of scale is impossible, or at least contrived. It's like comparing apples to tornadoes.
Given that basis, I can't start creating hierarchies based on feeling. I am no fan of relationship hierarchies, either - they each are what they are, and I'm not going to rank them.
I never refer to either of my partners directly as "my primary" or "my secondary", because I find that rather insulting on a multitude of levels. That doesn't negate the fact that I have a primary relationship and a secondary relationship - it describes the practical nature of the respective relationships, rather than their relative importance. Also, it can be fluid, based on the needs and circumstances.
Trying to compare relationships, than than just celebrating the individual nature of each, can lead into some rather dark places, including competitiveness, which in my opinion, should never be a part of a relationship.