It is narrated from Ibn Umar (may Allah be pleased with them both) that Umar bin Khattab (may Allah be pleased with him) wrote letters to the commanders of the armies regarding those men who are absent (from home) and not with their wives. He ordered them to hold such men accountable, that they should either provide maintenance to their wives or divorce them. And if they divorce them, then they should also give the maintenance for the period during which they did not provide for them.
Hadith Referenceمسند الإمام الشافعي / كتاب عشرة النساء والإيلاء والخلع / 1213
Hadith Takhrijصحيح موقوفاً: اخرجه البيهقي: 7/ 469 - وفى المعرفة السنن والآثار له (4748) - وعبدالرزاق (12346) ۔ و ابن ابی شیبة (19013)۔