Secondary, primary, poly etc they are all just labels, yes, and they have different meanings to different people. They were all labels I learnt, for ease of reference - not to confine things to a rigid structure, and poly fits more with my natural view of love also.
You expressed what I feel well, and I believe a lot of other poly people around here see it the same way from what I've seen, that there is no hierarchy in relationships except in the practical sense of who gets the biggest portion of your time/attention/commitment.
I never meant to imply that your other relationships outside your marriage are in some way less than your one with your wife. Sorry if it came off as such.
"This", for me at least, is usually my head. My heart knows what it wants but my head? My head thinks it can get it! Hah, if I could think the world to peace then there would be no more need for war.
So that I cause less confusion I'll just speak specifically from my own experience from here on out.
The more I focus on what I can't have the more I ache for it. The more I implied "I need poly or this is over" and gave no room for other solutions, the more black and white I was about life, the smaller my vision got and the more distressed my monogamous partner became. And the less willing to listen and consider me he became. I became very selfish for a time and we ended up just yelling our needs at each other, basically, and getting more and more hopeless and frustrated at the situation.
With his view point so drastically different from mine we had a lot of cross communication. When he finally felt that he could convey his feelings without me judging him - for example saying that he didn't approve of my choice in secondary since he didn't trust him, which I admitted I didn't either and started to re-think the budding relationship - the more we became allies again.
I was very afraid of being "forced" back into monogamy after only just realising that I could love more than one person ethically, honestly and happily - that people could and did. That was what I started to work on. My own fears, my own anger and frustrations. I cannot change him or how he feels. All I can do is remind myself of his good points, focus on them and watch them grow, and try to provide a space for him where he feels safe enough with me that - despite it possibly being against his true nature - he can explore becoming comfortable with me having other loves. Even if he never does become comfortable at least we'll have had a happy relationship, if I do find that I cannot go without other loves, or maybe we'll just end up happy despite everything.
The marker of a healthy relationship for me is one where all participants are growing.
This is just my experience and opinion; please take what you find useful and the rest with a grain of salt.