O! how thy worth with manners may I sing,
When thou art all the better part of me?
What can mine own praise to mine own self bring?
And what is't but mine own when I praise thee?
Even for this, let us divided live,
And our dear love lose name of single one,
That by this separation I may give
That due to thee which thou deserv'st alone.
O absence! what a torment wouldst thou prove,
Were it not thy sour leisure gave sweet leave,
To entertain the time with thoughts of love,
Which time and thoughts so sweetly doth deceive,
And that thou teachest how to make one twain,
By praising him here who doth hence remain.
To while away the hours during which he’s separated from his lover he thinks sweet thoughts of love itself. Absence, in this case, may not make the poet’s heart grow fond er  (he’s already as in love as he could possibly be), but it does at least bring comforting thoughts. 
 Compare  Antony and Cleopatra , Act 1, Scene 5 
 That I might sleep out this great gap of time My Antony is away.
Sonnet 39