All perfect praise be to Allaah, The Lord of the Worlds. I testify that there is none worthy of worship except Allaah, and that Muhammad is His slave and Messenger. We ask Allaah to exalt his mention as well as that of his family and all his companions.
Cordiality, intimacy and love are all noble objectives of a happy married life. This could be achieved if both spouses respect each other's rights and fulfill them in a good manners. Allaah says (interpretation of meaning): {…And due to them [i.e. the wives] is similar to what is expected to them, according to what is reasonable…}[2:228].
It is known that rarely a married life could be free from problems and ups and downs, but all good lies in being patient and using wisdom whenever one faces crises. So, each of the spouses should endeavor to make his partner happy, be patient, neglect the shortcomings of his/her spouse and give up some of his rights if possible to solve the problems. One should not resort to divorce except if there is no other choice. It makes Satan happy and destroys the family life and the children.
If this woman believes that they (husband and wife) are bewitched then she may seek cure by using Ruqyah (seeking cure by the recitation of the Qur'aan and the authentic supplications). She may even recite them on water or oil to use them as treatment. However, one should avoid going to fortune-tellers or soothsayers.
The above details show that this woman does not commit any prohibition if she makes Ruqyah without his knowledge rather it is a good deed and a kind act towards her husbands. The Prophet said: "Let he who can benefit his brother (in faith) do so." [Muslim]
Therefore, there is no harm – Allaah Willing – in helping this wife in that matter. You are not obliged to inform her husband about that but sometime it becomes compulsory to keep it as confidential.