One man proposes and says "I want to marry you because you’re better than every other woman I've dated". Another man proposes and says "I want to marry you because you're essential to me, and I can't imagine living without you." I see at least two ways to think about choosing a partner and loving others. There's one way, the one that I think is most common in my circles, and it sounds like "finding the best partner".
Something good about this but also the 2nd sentiment can easily come from someone who is infatuated and insecurely obsessed. A stable commitment is, as far as I can tell, made out of the recognition that THIS is worth betting on, given everything else you know about the world.
Source: had a first marriage. Just got married a 2nd time and everybody who was there seems to think I know what I'm doing (I know better, but I'm pretty sure I know enough.)
But then ONCE you've committed, then HARD YES. That person becomes essential, and is not to be compared to other people (but perhaps still compared: to the moon, or to goddesses, or to songs).
"Love is that condition in which the happiness of another person is essential to your own.” - Jubal Harshaw, from Stranger in a Strange Land, by Robert A. Heinlein.
Omg, it's so adorable! And so true! Love it! - essentially ;)