What is the ruling on a new Muslim husband continuing to communicate by phone with a girl who is not a mahram to him, under the pretext of academic matters, especially since this communication causes marital problems?

Conversation with foreign women for no need is one of the greatest doors to fitna (strife/temptation), and it has led to much evil and corruption. Ibn al-Jawzi said: "The conversation of foreign women and being alone with them works within one's inner self, while they are heedless of it, until they perish." Their error was twofold: violating Islamic law and exposing their nature to what it was created for.

A Muslim should avoid conversing with foreign women except for an essential need. If the man is a recent convert to Islam, one should be gentle in advising him, as he may have been brought up with such practices.

Excuse him for his ignorance of the ruling, and explain to him that Islamic law prohibits this to preserve religion and honor and to seek chastity. Warn him of the bad consequences of such actions, but do not approach the matter with harshness, rather with concern for his faith. Speak to her (the foreign woman) as well and advise her gently, do not speak ill of her, be patient, and seek help through du'a (supplication).