Because through nights like this one I held her in my arms my soul is not satisfied that it has lost her. Her infinite eyes.
Having invested a great deal emotionally and financially in the book, Neruda was elated when Crepusculario was first published. However, the eloquent, bittersweet lines that follow suggest that in this line he is trying to distance himself from the memory of his love for her and so ease his suffering.
It repeatedly refers to itself as a poem in progress, not a finished piece.
One could say that he is grossly overstating the intensity of his emotional state, but try telling that to someone who has lost a lover. He apparently felt constrained by traditional forms, yet was apprehensive about breaking free of the kind of verse which was readily accepted.
Here the speaker is left with the surging memory of his lover in a deep lament expressed in terms of coastal, sea imagery.