Is the wife's unwillingness to return to her husband and her request for a divorce, despite attempts to reconcile her, due to her personal desire, or is what she is suffering from, namely sorcery, the reason, especially after the husband learned of her pregnancy?

It is not possible to determine with certainty the reason for the wife's aversion and her demand for divorce. It could be due to magic (sihr), or it could be due to pregnancy sickness (al-wahm) which can cause her to dislike her husband and become fed up with the most trivial things; this is a temporary phase.

One should be patient and continue with ruqyah (exorcism/spiritual healing) and supplication (du'a), as often the newborn child becomes a source of affection.

If she insists on divorce after the pregnancy ends, then let wise people mediate for reconciliation. If she does not come to her senses, then divorce her. You have the right to refuse divorcing her until she ransoms herself with money.