I'm a "secondary" and after reading all this, find that I suffer a dilemma that has so far been unmentioned.
Who is primary and who is secondary? My girlfriend lives with her husband and they've been married twenty years. They have children together, work at the same company, and share many routines. Her home and family are very important to her. By all standard definitions, he is her primary. But this is only one spectrum, let's call it the home spectrum. I'll add here that my home is on this spectrum too and she has watched the sunset from my couch, loved my cat, used the shower, helped cook supper, owns a key to my house, and knows my bed intimately.
There is also a love spectrum. There, her and I share romance, passion, connection, and happiness beyond what they find together. You could say that her and I are emotional primaries. Let me emphasize here that she loves her family too. They share friendship, love from and for their children, a love of music, open minded attitudes, and commitment to each other. Her husband is a nice guy.
My dilemma arises when I consider the primacy of the emotional relationship we share versus being secondary in so many other aspects of the relationship. I struggle, knowing I have all of her in many ways and yet little of her in many others. It makes me want to have more of her in all ways but I realize that the time she gives me is time that is taken from others who need her too. It makes me feel guilty for wanting more of her. I have good reason to suspect that her husband also experiences dilemmas concerning the nature of primacy in the different aspects of our relationships.