The word is a trap. In common usage, jealousy means suspicion, control, going through a phone. That is not what Sheikh Muhammad Said Raslan is talking about.
What he classes as a mistake
The sheikh ranks among the mistakes of husbands the lack of protective jealousy toward the wife. That is the opposite of what one expects, and it is what makes the passage interesting.
He gives the definition: jealousy is a noble feeling, one of the feelings of true love. It drives the husband to protect his wife, and invites the wife to safeguard her husband.
The key word is protect. The jealousy he speaks of faces outward, like a guard. It does not face the spouse, like a suspicion.
A quality that does not depend on feeling
Sheikh Raslan adds a detail that settles a real case: it must never weaken in a man, even if he does not love his wife, he remains jealous over her as long as she is under his protection.
In other words, protection is owed independently of felt affection. That is consistent with what we see in is love a condition of marriage: the feeling varies, the duty does not.
What it produces
The sheikh closes on a return effect: jealousy makes the spouses feel love and affection, and prompts them to revive that love, to make it grow and to care for it.
It is therefore both a sign and an engine. Where it disappears entirely, what is usually found is not serenity but indifference.
The limit, which is not in this text
The sheikh describes a virtue. He does not describe permanent surveillance, accusation without proof, or cutting a wife off from her family and relatives.
Those behaviours fall under what the same scholars condemn elsewhere: humiliation, harshness, and trying to straighten the other by force. We cover them in treating your wife well and domestic violence in Islam.
The practical difference is simple to state. A jealousy that protects is directed at what comes from outside. A jealousy that harms is directed at the person one is supposed to be protecting.