Conversely, if a man who has been repeatedly refused, or who for some other reason endeavours to suppress his passion, feels in doubt whether the cure is complete, he need only imagine his former love in the arms of another man, or before the altar with him: if that does not make him turn pale and frown and bite his lips, he is cured. This test, however, is not so certain as the other, for sometimes Jealousy outlives Love; and Longfellow believed that every true passion leaves an eternal scar.
Like Coyness, Jealousy is a discord in the harmony of Love. A little of it is piquant and rouses desire. “Jealousy,” says Hume, “is a painful passion, yet without some share of it the agreeable affection of love has difficulty to subsist in all its force and violence.... Jealousy and absence in love compose the dolce piccante of the Italians, which they suppose so essential to all pleasure.”
Unfortunately, Jealousy is rarely content to remain “agreeably piquant,” but is apt to grow into a tornado of passion which devastates body and soul, and makes it the keenest agony known to mankind. It is often said that the agony inspired by a refusal is the only thing that excuses tears in a man. This agony is a mixed emotion, including wounded Pride and the sense of having lost all that makes life worth living. But its keenest sting comes from the green-eyed monster, who hisses into the lover’s ears that now a rival will enjoy her sweetness and beauty. Dante did not correctly describe the lowest depth of hell: it is this thought in the lover’s mind that “now another will marry her.” It is that thought which drives lovers to lunatic asylums and suicide.
“Some lines I read the other day,” Keats wrote to Fanny Brawne, "are continually ringing a peal in my ears—
“To see those eyes I prize above mine own
Dart Favours on another—
And those sweet lips (yielding immortal nectar)
Be gently press’d by any but myself—
Think, think, Francesca, what a cursed thing
It were beyond expression.”