Is the breaking of an engagement because the fiancé is unable to control himself – according to the fiancée – considered an injustice to him, or a denial of Allah's blessings?

There is no blame upon you for breaking off the engagement due to what became apparent to you regarding the suitor's character, and there is no injustice to him in that. However, we advise you not to break off the engagement and to proceed with the matter if you hope for his reform and righteousness. The suitor is a stranger to his fiancée; it is not permissible for him to be alone with her, or to touch her, or to look at what is not lawful for him to look at of her. If any of that occurred, then you both must make sincere repentance. If you decide to break off the engagement and seek someone else of good character and religiosity, then there is no blame upon you.