3.3 line 168 what does that meam? and what n how did he explain it to his readers
The lines you refer to are spoken by Iago, Othello's ensign and the character most often seen in literature as evil personified. In Act III scene iii Iago is torturing his master by implying that Othello's wife Desdemona has been unfaithful with Cassio, a trusted employee. In these lines Iago is telling Othello to beware of jealousy as it sustains itself and lives off itself, festering and growing fuelled by supposition and doubt. He says that even those men ('cuckolds') whose wives are unfaithful are in a better position than Othello as they usually do not know, or 'love' the man who has wronged them.
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!
"Othello" - William Shakespeare
