Is the husband entitled to reclaim the dowry or part of it, and take the gifts (gold and otherwise) that he or his family presented to his wife, if he wishes to divorce her after six months of marriage due to his aversion to her and his suspicion that she had an illicit relationship before marriage?

The dowry is a right of the wife, and it is not permissible to revoke it or any part of it, based on the words of the Almighty: "And if you want to replace a wife in place of another, and you have given one of them a qintar [a great amount of wealth], do not take anything from it. Would you take it in slander and manifest sin? And how could you take it while you have gone into each other, and they have taken from you a solemn covenant?"

Likewise, what was given to her as a gift is not permissible to revoke after she has taken possession of it, based on the words of the Prophet, peace and blessings be upon him: "It is not permissible for a man to give a gift or bestow a present and then revoke it, except for a father concerning what he gives to his child. And the one who gives a gift and then revokes it is like a dog that eats until it is full, then vomits, and then returns to its vomit."

The affairs of a Muslim should be interpreted with integrity and good presumption, based on the words of the Almighty: "O you who have believed, avoid much [negative] assumption. Indeed, some assumption is sin." If you divorce your wife, do not speak with this assumption, lest you become sinful.