Thank you so much for mentioning this. I did not know about this whole chapter in Sam's life after Frodo leaves. I just see now that Tolkien notes in an appendix that Sam did follow Frodo to the Undying lands, and so the epilogues are like chapters leading up to that reunion.
The epilogue exists in two versions. The second, in addition to the part you quote, has Sam in the process of becoming a writer who can add chapters to Frodo's book that incorporate into the existing work--achieving what Sam calls "proper style, somehow."
In his later years then it seems he had two great tasks : being a husband and father, but also realizing a higher marriage to Frodo that occurs textually. When Rosie dies, and with the book finished, Sam then rejoins Frodo forever.
I read a fascinating 2018 paper on the epilogues (by Nicole duPlessis) that compares the language around Sam's devotion to Frodo in his later years with Tolkien's own devotion to the Eucharist.
She writes: "In the connection between Sam and Frodo, we see a devotion that leads to eternity—or at the very least, to divine healing. Sam’s eventual journey to the West suggests that Sam has, along with Frodo, undergone a kind of religious conversion in which he sees what is True, is made fit to love that Truth, and cannot fully go back to being a hobbit, although he acts the part for a very long time."
The bond of Frodo & Sam then seems to become the basis for a romance that becomes a spirituality. Where the earlier age had Beren and Lúthien as its signature lovers, the new age has the romance of Frodo and Sam. A queer spirituality at the heart of LOTR.
* I posted the duPlessis paper online:
