Sonnet 39 by Shakespeare

Sonnet 39 is one of 154 sonnets written by the English playwright and poet William Shakespeare. It is a member of the Fair Youth sequence, in which the poet expresses his love towards a young man.

Paraphrase
How can I celebrate your worth in my poems without appearing conceited, given that you're my better half? What good does it do me to praise myself--and am I doing anything besides praising myself when I praise you? For this reason, let's live apart. And though we love each other dearly, let's lose our common identity; by this separation, I can give you the praise that you deserve by yourself. Oh, absence, you would be such a torment if it weren't for the fact that you give me the chance to fill up the lonely hours with thoughts of love, which make the time pass so sweetly, and that you teach me how to divide my love and me in two, as I, here, praise my friend while he remains elsewhere.

Themes
Sonnet 39 is about the necessity of separation. The last few lines could cause some confusion; the poet is saying that, although he is separated from his lover, and therefore 'twain' or divided, they are really still the same. This can be so because of the sweet thought of love guiding the poet, allowing him to show that his lover is still within his heart and thus joined to him in spirit, no matter where his lover is in body. No one knows for sure the true identity of Shakespeare's dear friend, but most scholars agree that he was the Earl of Southampton, the poet's patron.