Is it advisable to continue supplicating for the deceased, reciting Qur’an for her, and visiting her grave, after discovering that she had been in an illicit relationship (zina) before her death?

It is not permissible to accuse a wife of adultery without four righteous witnesses. The woman has passed away, and she is in greater need of supplication and seeking forgiveness. Therefore, it is advisable to supplicate for her forgiveness, mercy, and pardon, so that perhaps Allah may forgive the questioner and pardon him.