What is the maximum time for a man to leave his wife alone?

What is the maximum time period for a man to leave his wife separate without having sexual intercourse between them? (For instance, he went to a foreign country to earn a living.) I heard that at the time of Umar(R.A), he made a fatwa of "four months period is the maximum time for a women to control herself from haraam without husband, so who even went for jihad should return after four months to fulfill his wife's Haq". What is the fatwa of Shia and Sunni scholars about this?