I was sure it was in the sequel, but if the sequel is part of the book in the US, it explains it.

Yes, and it also explains how I ended up with an extra "half a book" when I decided to catch up on my Alcott reading. :-) I ordered copies of all the books I didn't have, which included Good Wives. (Which I indeed had read a bunch of times as the 'second half' of Little Women without knowing it, of course).