Jealousy

O, beware, my lord, of jealousy!
It is the green-eyed monster, which doth mock
The meat it feeds on. That cuckold lives in bliss
Who, certain of his fate, loves not his wronger;
But O, what damned minutes tells he o'er
Who dotes, yet doubts--suspects, yet strongly loves!

William Shakespeare,
Othello
The Moor of Venice