Was his action right when he concealed the details of his future housing plans from the girl he intended to marry, who had stipulated not living in a certain area, or should he have informed her of all the details of his future life?

The fiancé is a stranger to his fiancée, and he should not speak to her or correspond with her except out of necessity and to the extent of that necessity. You are not obliged to inform her of the details of your future life, and there is no harm if you inform her about the housing matter. Since you have left her, do not dwell on what has passed and seek out other righteous women.