What should I do to please Allah and my husband after looking at a handsome young man, and what is the ruling of Sharia on this action?

The wife who erred and repented is advised to increase in acts of obedience, repent for what she did, show her love for her husband, endear herself to him, adorn herself for him, and persistently supplicate to Allah to grant her contentment, make her beloved to her husband, and make her husband beloved to her. As for the husband, he should not be harsh in his treatment, for gentleness adorns everything. Since his wife has admitted her mistake and regretted it, there is no need for his anger to persist.