No more be grieved at that which thou hast done,
Roses have thorns, and silver fountains mud,
Clouds and eclipses stain both moon and sun,
And loathsome canker lives in sweetest bud.
All men make faults, and even I in this,
Authorizing thy trespass with compare,
My self corrupting salving thy amiss,
Excusing thy sins more than thy sins are:
For to thy sensual fault I bring in sense,
Thy adverse party is thy advocate,
And 'gainst my self a lawful plea commence:
Such civil war is in my love and hate,
That I an accessary needs must be,
To that sweet thief which sourly robs from me.

William Shakespeare

http://www.poemhunter.com/poem/sonnet-35-no-more-be-grieved-at-that-which-thou-hast-done/