What a lovely, clear, and relatable explanation of the central "opportunity" presented by relationships. And of the difference between those first excited feelings and enduring love. It soothed me to read such a well considered and like-minded piece. Seeing myself reflected in the frustration and sometimes disgust of others has been critical to my healing.
I'll have to think about the idea of infatuation as a selected trait. It makes some sense but is hard to imagine it in the environments of evolutionary adaptation when mate choices were much more limited. Maybe it helped our ancestors feel motivated to hop to new tribes with minimal information and "dating?"