In my case, when I take on a lover, our hearts are connected such that I'm with and for them utterly. This will be so if one of my partners can't spend as much time with me as the other/s. It's just how I love. I love equally. I really do.
I also believe that I love equally. But I cannot spend an equal amount of resources (time, attention, money, etc.) on each of my partners. And they don't have the same amount to give to each other their partners.
I do prioritize in terms of where I believe my largest amount of responsibility lies -- my husband followed by my other partners followed by my friends followed by acquaintances followed by strangers.
We use the terms primary and secondary because they accurately describe how we function. Yes, some people may take the term secondary to mean disposable. I've experienced this. But I've also experienced situations where it didn't mean that. Until we find better terms, I'll continue to use them....