“some people fall in love over and over again while some people can only do it once.”

Source: Summer in the City

~ "Burrito"
Song lyrics

Source: Sugar Daddy

Noah Calhoun, Chapter 1, p. 25
2000s, The Wedding (2003)

Wilson Lewis, Epilogue, p. 262-263
Variant: But most of all, I learned that it’s possible for two people to fall in love all over again, even when there’s been a lifetime of disappointment between them.
Source: 2000s, The Wedding (2003)
Context: The events of the past year have taught me much about myself, and a few universal truths. I learned, for instance, that while wounds can be inflicted easily upon those we love, it's often much more difficult to heal them. Yet the process of healing those wounds provided the richest experience of my life, leading me to believe that while I've often overestimated what I could accomplish in a day, I had underestimated what I could do in a year. But most of all, I learned that it's possible for two people to fall in love all over again, even when there's been a lifetime of disappointment between them.

Source: https://www.globalcitizen.org/en/content/15-quotes-from-chimamanda-adichie-that-have-change/

"Let's Do It, Let's Fall in Love" (there have been many variant renditions of this song by various artists).
Paris (1928)

Oscar Levant, as recounted by Levant in A Smattering of Ignorance (1940); quoted in "Books and Things" by Lewis Gannett, in The New York Herald Tribune (January 13, 1940), p. 11