Praise be to Allah.
If an amulet is made with something other than Qur’aan or du’aa’s narrated from the Prophet (peace and blessings of Allaah be upon him), or if it contains symbols, mumbo-jumbo and strange words that cannot be understood, then there is scholarly consensus that it is haraam and constitutes shirk. But if the amulet is made with Qur’aan or du’aa’s narrated from the Prophet (peace and blessings of Allaah be upon him), then there is a difference of opinion among the salaf, but the correct view is that it is haraam. See question no. 10543.
The scholars of the Standing Committee said:
The scholars are agreed that it is haraam to wear amulets if they are made with anything other than Qur’aan, but they differed concerning those that are made with Qur’aan. Some said that it is permissible to wear them and some said that that is not permissible. The view that it is not allowed is more likely to be correct because of the general meaning of the ahaadeeth, and so as to prevent the means that may lead to shirk.
Fataawa al-Lajnah al-Daa’imah, 1/212
So you and your wife who asked you for this amulet should remove it straight away and burn it. You said that you did that and you did not know that it was shirk, so you are not to be regarded as a mushrik or a sinner because of this action, since you did not deliberately commit an act of sin. Allaah says (interpretation of the meaning):
“And there is no sin on you concerning that in which you made a mistake, except in regard to what your hearts deliberately intend”
“Our Lord! Punish us not if we forget or fall into error”
And the Prophet (peace and blessings of Allaah be upon him) said: “My ummah is excused for their mistakes, what they forget and what they are forced to do.”
This evidence indicates that whoever commits a sin but does not know it is a sin, is not to blame, and that Allaah has forgiven him.
And Allaah knows best.