What does "Let nothing unite us, so that nothing can separate us" mean?

Question

Let nothing unite us, so that nothing can separate us.

This quote is from the second stanza of the poem "Farewell" (English translation) — the original Spanish text is

Para que nada nos amarre que no nos una nada.

Does this mean that if you love someone, you should "set them free"?

Answer 1

I tend to think that Neruda is talking about the possibility or potential of the man in the poem engendering a child with the unnamed woman and that, were this to occur, this potential child (or the life flowing through the child’s veins) would then, through her/his existence, “ground”him (a “sailor” who, instead, would like to have a woman waiting at every port). Meanwhile he is likely playing here with the words “amarrar” - “to tie up, to bind” - and “amar” - “to love.” Later in the poem he also seems to play with “a amar” and “a mar” as in “to love” and “to the sea,” probably explaining his introduction of the male lover as a sailor.

The line quoted is also full of alliteration and semi-hidden meanings:

Para que nada nos amarre que no nos una nada.

For example the word “nada” means “nothing” and “swims,” as in “una nada” or “a female swims.” Moreover, the word “una” means “joins,” which carries the surface meaning of “nothing join (us)” as well as “a nothing(ness)”.

Answer 2

Reading the entire poem, I think it is clear that he is talking about a child.

DESDE el fondo de ti, y arrodillado,
un niño triste, como yo, nos mira.

The narrator is the father of the child, but he does not want to have a child ("YO NO lo quiero, Amada"/ "AMO el amor de los marineros / que besan y se van. / Dejan una promesa. / No vuelven nunca más.", etc.). So he is saying that he does not want to be tied ("amarre"), so he does not want anything to tie/unite them (the kid).