Francis Beaumont - The Indifferent

Never more will I protest,
To love a woman but in jest:
For as they cannot be true,
So, to give each man his due,
When the wooing fit is past
Their affection cannot last.

Therefore, if I chance to meet
With a mistress fair and sweet,
She my service shall obtain,
Loving her for love again:
Thus much liberty I crave,
Not to be a constant slave.

But when we have tried each other,
If she better like another,
Let her quickly change for me,
Then to change am I as free.
He or she that loves too long
Sell their freedom for a song.

Francis Beaumont

http://www.poemhunter.com/poem/the-indifferent-3/