I relate to it as the primary has more. It is not a choice. It happens naturally. Love can fade. Therefore it is sometimes stronger than at other times. Sometimes love fades in a relationship and they meet someone new. The love is new, therefore they might love the new person more than their existing partner. I read all the time that some wives don't love their husbands as much as they used to. It happens to men also.
I think you might be confusing the fading of love to the natural ebb and flow of a long-term relationship. Once you get past the NRE aspect of a relationship, there comes ebb and flow. There are lots of factors there, life being the biggest one.
My primary is my husband. He knows it's not because i love him more. I, like some others, can't quantify love. I love, period. The best I can do is learn to not let myself get carried away to the point of letting myself be a doormat for love. Yet, that's my issue, not love's.
My husband is my primary because we have been together twenty years, have intermingled our lives that long, our plans, our children, our house, our future plans, all intermingled in a way that no other relationship is. Does that mean no other relationship ever will? Who knows? But it would sure take a long time!
Do I at times have more ebb than flow with hubby or bf? Sure, but that doesn't mean I love one more than the other! It typically means that I get to wanting to curl up in their laps, want to jump their bones, or just make sure to spend more time together. It ebbs and flows. Sometimes I'm just tired; they are tired; we are sick, busy; worn out. It's the kids; jobs; life!
Another thing is that you put a
lot of emphasis on whether or not she wants one dick more or less than another, and the size of it. You know what works for you, works for you, but that is
not how it is for everyone. Who I want more, physically or emotionally, has never had anything to do with whose dick is bigger, or who I enjoy having sex with more than the other, probably because, for me, whom I enjoy having sex with is more dependent on things like NRE, hormones, and other factors, rather than the size of their cock.
(If I want a specific size, I can freakin' buy it. I prefer who's attached to the cock itself. Silly me.)