Putting on my tin hat and wading into Devil's advocate position:
Why should the relationship my lover has with someone else be given more weight and consideration than the relationship he has with me?
Perhaps because your lover gives it more weight and consideration? I think many people who take a hierarchical approach to poly do so because they actually love their primaries 'more' than their secondaries, in some sense. That might be all you need to know to get the hell out of dodge and DTMFA, but perhaps you might find that the level of your feelings for this lover are actually well matched. You find that you've reached an equilibrium, and that you're not wanting further connection. That as long as the primary relationship isn't disrupting the time you have with your lover, and that it all runs smoothly and without hysterics, that actually it can still be a relationship in which you want to invest, are able to invest, and feel works for you.
Because they've given themselves the title of Primary and I will never be that?
It takes two to tango. If this is not being imposed upon your lover by his primary, if this is what he wants too, then it seems like your issue is with him and not the other party. There is no 'decree from on high', only an upfront acknowledgement that he's not up for investing equally in both his relationships, because he's happiest that way.
Psh! I'm not chopped liver, I am a person who deserves just as much respect as anyone else he is involved with. I deserve to be valued just as much as anyone else he involved with, and I should be able to make my own choices about my relationship without getting permission from anyone. I deserve to be listened to and heard when I express myself, as much as anyone else he is involved with, and I should feel safe within my relationship without wondering whether his primary partner is going to pull some bullshit move.
Absolutely this. Not even a Devil's advocate could argue with that.
The only bit that I would jump on is the bit about his primary pulling some bullshit move. That kind of thing doesn't happen without your lover's consent. So really, if he agrees to that, then it's because he's making a choice to let your relationship go because other things are more important. Yes, that sounds crappy, but is that not always why break-ups happen? Because one or both parties decide that the relationship no longer works for us for some reason?
What the hell are these Primaries protecting their relationship from anyway, if you think about it? From anyone else mattering a great deal to their partner? Well, boo-hoo for them if a lowly secondary actually matters and is someone their freaking partner cares about, ugh. How selfish and stingy it is to have a couple-centric approach in poly.
I think my general point is that you'd only be dropped like yesterdays cold dinner if you actually didn't matter a great deal to them. Or else that being with you was causing such a strain that overall, the negatives were outweighing the positives. And again, I feel like those situations can arise anyway, even in non-hierarchical relationship dynamics. I've chosen to walk away from people I've cared about a lot, because in the greater scheme of my life, that relationship was holding me back in some way. I'm not sure it makes a difference what the cause of that is; just knowing that your lover is making a call for their own good. That might be selfish, but then, you could argue we are all being selfish anytime we have priorities.
The temptation when you are a secondary (and I know, I have been there) is to always think that the rules are coming from the primary partner - not your own. I call bullshit on that. Plenty of people put limits on themselves in order to not upset the balance of their own lives. I respect a person's right to have priorities and to conduct their life according to what makes them happiest. As long as they are not misleading me, and as long as they have the strength of character to speak up if their priorities change, then to me it's ok.
You may slay me now.