If you're at all interested in either morality or religion, I would recommend this one. At a bit over 800 pages, it may not be the densest of the wisdom books. Here's it on jealousy:

It is hard to imagine what some jealous men can make up their mind to and overlook, and what they can forgive! The jealous are the readiest of all to forgive, and all women know it. The jealous man can forgive extraordinarily quickly (though, of course, after a violent scene), and he is able to forgive infidelity almost conclusively proved, the very kisses and embraces he has seen, if only he can somehow be convinced that it has all been "for the last time," and that his rival will vanish from that day forward, will depart to the ends of the earth, or that he himself will carry her away somewhere, where that dreaded rival will not get near her. Of course the reconciliation is only for an hour. For, even if the rival did disappear next day, he would invent another one and would be jealous of him. And one might wonder what there was in a love that had to be so watched over, what a love could be worth that needed such strenuous guarding. But that the jealous will never understand. And yet among them are men of noble hearts. It is remarkable, too, that those very men of noble hearts, standing hidden in some cupboard, listening and spying, never feel the stings of conscience at that moment, anyway, though they understand clearly enough with their "noble hearts" the shameful depths to which they have voluntarily sunk.