The speaker begins by declaring that, tonight, he is capable of writing the saddest lines of poetry. He offers an example of one such line, which describes the desolation of the sky on a cold, windy night. He then repeats his assertion that he can write the saddest verses, declaring that he loved "her," and that she loved him back. He recalls holding and kissing this former lover under the stars, and remarks on the beauty of her eyes. Tonight, though, he dwells on his loss of her. The night feels overwhelmingly vast in her absence, and poetry comes to the speaker like dew on grass.
It doesn't matter that the speaker wasn't able to keep the lover, when he is left without her on a starry night. He hears someone singing far away, and his soul is not able to accept that she is gone. Through his senses and feelings, he seeks her out without success. The night and the trees haven't changed, but he and his lover have: though he's not even in love with her, he once was, and his voice sought out the wind so that she would hear him.
One day, the lover will belong to someone else, just as she did before she loved the speaker. He doesn't love her, he says, but then reconsiders and wonders if he still does. In any case, the process of forgetting is longer than the process of being in love. On these nights, similar to the ones where he once held his lover, he's unable to accept the loss. However, he claims, after this night he won't suffer because of her any longer, and he won't write any more poems about her.