Never waste jealousy on a real man: it is the imaginary man that supplants us all in the long run. – George Bernard Shaw

Every other sin hath some pleasure annexed to it, or will admit of an excuse: envy alone wants both. – Robert Burton, The Anatomy of Melancholy

Jealousy lives upon doubts. It becomes madness or ceases entirely as soon as we pass from doubt to certainty. – Francois de La Rochefoucauld

That is ever the way. Tis all jealousy to the bride and good wishes to the corpse. – J. M. Barrie