How did jealousy destroy Leontes? Give three examples.

Does Leontes become jealous?  Yes.  Does it "destroy"
him?  All things considered, since he is reunited with both his wife and daughter at the
end of the play, he is not truly destroyed.

By the end of
Act III, it would appear that he is destroyed.  In Act III, scene 2, Pauline confronts
the jealous tyrant and enumerates all that he has done in his unfounded jealous
anger.

In his jealousy, he betrayed his best friend,
Polixenes.  She tells him that to send away his baby daughter to be left alone in the
wild was an evil action.  She also lays the death of the young prince at Leontes's
feet.  Finally she tells him that he is responsible for the death of
Hermione.

In rejecting the Oracle's answer, Leontes brings
down the wrath of the gods and until what is lost is found (Perdita) Leontes will remain
a broken man.

For what it is worth, when Patrick Stewart
played the role, he asked a psychiatrist friend to help him understand Leontes who
appears to become jealous out of the blues, so to speak.  What his friend discovered was
that the jealousy we see is actual a real mental illness that mimics jealousy but
progresses in stages, just like Leontes.

First this
unfounded jealousy seems to come on suddenly and usually the wife is suspected to have
had an affair with the best friend, although there is no
evidence.

Secondly there is a desire and attempt to kill
the friend and a rejection of the wife.

Thirdly there is a
deep depression that can last days, weeks, and even
years.

According to Stewart, this information helped him as
an actor to understand his character.

Shakespeare was a
great observer of his fellow man and this is just another
example.