What should a young man do about his ex-fiancée, after they separated following a dispute, and she then became engaged to another man, yet claims she is unhappy and cries frequently, even though she concealed the details of their previous relationship from her current fiancé?

It is not permissible to propose to an already engaged woman if she has inclined towards her first suitor, based on the Prophet's (peace be upon him) saying: "A believer is a brother to a believer. It is not lawful for him to buy over his brother's sale, nor to propose over his brother's proposal until he gives it up." However, some scholars have permitted proposing over another's proposal if the first suitor is corrupt. It must be understood that it is not permissible for a man and a woman who are not mahram to each other to form a relationship or friendship. For one who wishes to propose to a woman, it is legislated that he may look at her to that which would encourage him to marry her, without being in seclusion with her.