Is remembering childhood memories with a female cousin and having them come to mind considered a sin for which one will be held accountable? And does saying to her: "If you divorce your husband for a legitimate reason, unrelated to your love for me, then you now know – because of my mother – what is in my heart towards you, and perhaps Allah will unite us again," fall under incitement? And is it permissible to marry her if she is divorced?

The relationship of love between young men and women is not sanctioned by Islamic law. If one's heart becomes attached to a woman without pursuit, then the lawful course of action is to propose to her, provided she is not married. The mother erred by informing the married woman of the questioner's desire to marry her, and the questioner erred by speaking to her and hinting at his desire, for scholars have agreed on the impermissibility of hinting at a proposal to a woman in revocable divorce ('iddah), so how much more so for a married woman?

It is not permissible to propose to a married woman, neither explicitly nor implicitly, as this is an unlawful act of corrupting her relationship with her husband. Ibn Taymiyyah said: "As for the married woman, it is not permissible to propose to her, neither explicitly nor implicitly. Rather, that is corrupting a woman against her husband, and it is among the most heinous sins." The Messenger of Allah (peace be upon him) said: "He is not of us who corrupts a woman against her husband or a slave against his master." Some scholars do not validate the marriage of a woman to the one who corrupted her against her husband.

As for intrusive thoughts and dwelling on memories, a person is not held accountable for mere self-talk, based on the saying of the Prophet (peace be upon him): "Indeed, Allah has forgiven my Ummah for what they talk to themselves about, as long as they do not act upon it or speak of it." However, indulging in such thoughts opens the door to temptation and corruption, and these thoughts are the seeds of Satan and the self that lead to actions.

One must repent to Allah, turn away from this married woman, and focus on what benefits in religious and worldly matters. If this woman is divorced by her husband, there is no harm in marrying her after her waiting period ('iddah) has expired.