What is the solution for someone who suffers from loneliness while abroad, and is afraid of falling into sin because his wife is away studying?

If it is possible for the husband and wife to be together in one place to continue their studies, that is preferable. Otherwise, it is obligatory for the wife to obey her husband by moving to him, based on the Prophet's (peace be upon him) saying: "Obedience is only in what is right and lawful," and his saying: "If I were to command anyone to prostrate to another, I would have commanded the woman to prostrate to her husband." It is a condition that the study be permissible and free from forbidden things.