William Shakespeare - Sonnet 110:

Alas, 'tis true I have gone here and there
And made myself a motley to the view,
Gor'd mine own thoughts, sold cheap what is most dear,
Made old offences of affections new.
Most true it is that I have look'd on truth
Askance and strangely: but, by all above,
These blenches gave my heart another youth,
And worse essays prov'd thee my best of love.
Now all is done, have what shall have no end!
Mine appetite, I never more will grind
On newer proof, to try an older friend,
A god in love, to whom I am confin'd.
Then give me welcome, next my heaven the best,
Even to thy pure and most most loving breast.

William Shakespeare

http://www.poemhunter.com/poem/sonnet-110/