What is the ruling on a woman traveling for study for three years, with her husband's approval and the presence of a mahram?

If the husband consents to his wife's travel, and she has a mahram with her, and she feels safe in the country of travel, then there is no impediment to that. However, it should be noted that the gathering of spouses has great benefits, and their long separation may lead to religious, psychological, and social harms and corruptions. A wise person weighs benefits against harms. It also warns against the danger of traveling to disbelieving lands, regarding faith and morals. Residence there is permissible in specific cases and with regulations.