Summary
Shelley believes in the Platonic love, which shuns fulfillment. It is a desire that always remains unsatisfied. In love, Shelley must find something ideal, something ever to aspire after, something ever to look forward to. It is in the expectation of fulfillment that his happiness lies. H has expressed the Platonic conception of love in this beautiful stanza.
The poet says that when rose petals wither away, they do not become useless. They retain their sweet smell even after withering away. That is why they are used for decorating the beloved’s bed. The poet’s beloved has been separated from him. She is not with him, but her thoughts are with him and his love will sleep on her thoughts.
In other words, the poet wants to say that it does not matter if the sweetheart is physically away from him because spiritually she is with him. He is not alone as in his imagination he finds his beloved very close to him. Separation has sharpened love but he is free from mental agony as her sweet thoughts always comfort and soothes him. His love is passionate and profound and it will not change with the passage of time. He cannot forget his beloved and will continue to love her in his imagination as true love does not die and transcends all barriers and surmount all obstacles. Absence sharpens love; distances intensify love but imagination brings the beloved so close to the lover that distances come to end and the two separated souls are united.