What should I do about my fiancé who has a history of doctrinal corruption and sins (fornication and drinking intoxicants), and despite his claim of repentance and starting to pray three years ago, he expresses dissatisfaction with my physical appearance, while my parents insist on completing the marriage to him and I do not wish to do so?

The default assumption for a Muslim is soundness. If your accusation against your husband of corrupt creed is not based on clear evidence, then you have erred, for his past alone does not warrant a judgment, as he may have repented.

You must investigate. If he is still adhering to a corrupt creed that is considered among the nullifiers of Islam, then your marriage to him is void, and you must separate from him. However, if his situation has not reached the level of disbelief, then the marriage is valid.

If you fear harm from staying with him, or if you dislike him and fear neglecting his rights, then you have the right to seek divorce or khul'. Try to convince your parents to agree to your separation from him. If they insist on your staying with him, you are not obliged to obey them in this, for obedience is only in what is good and permissible, and it is not good for a wife to remain with a man from whom she may suffer harm by her continued presence.

We draw attention to two matters: First: Whoever is afflicted with a sin is not permitted to uncover Allah's covering and inform anyone of having committed it. Second: If a woman is contracted to a man, she becomes his wife, and what is permissible for a husband from his wife becomes permissible for him, while observing the custom regarding the deferral of consummation.