First of all, it is to be stressed that the relations between the spouses should be based on tranquility, love and mercy. Allah says, “And among His Signs is this, that He created for you mates from among yourselves, that you may dwell in tranquility with them, and He has put love and mercy between your (hearts): verily in that are Signs for those who reflect.” (al-Rum 30:21)
The husband and wife should care for each other. Their relationship should be based on mutual understanding, respect, and they should have mercy and kindness for each other.
Dr. Marawan Shahin, Professor of Hadith and its Sciences, Faculty of Usul Ad-Din, Al-Azhar University, states the following: “First of all, a husband should let his wife accompany him as long as this is not impossible or extremely difficult. `A’ishah (may Allah be pleased with her) reported: “Whenever Allah’s Messenger wanted to go on a journey, he would draw lots as to which of his wives would accompany him. He would take her whose name came out.”
The general rule is that a husband should let his wife to accompany him on his journey regardless of the costs, and whether or not it will decrease his savings.
This is because by being together, the spouses will be in an atmosphere that will enable them to preserve their chastity and be away from haram.
However, if there is a necessity that renders it extremely difficult for the wife to accompany her husband, then he should seek her permission before traveling alone. If she willingly agrees, then he is still required not to be away from her for more than four months and to try his best to lessen this period as much as he can.

One night Caliph `Umar Ibn Al-Khattab (may Allah be pleased with him) was making his rounds of Madinah when he heard a woman singing and complaining of being alone, deprived of her husband. Upon investigation, `Umar (may Allah be pleased with him) found that the woman’s husband had been on a military expedition for a long time. He then asked his daughter, Hafsah, a widow of the Prophet (peace and blessings be upon him), “How long can a woman endure separation from her husband?” She replied, “Four months.” As a consequence, he decided that he would not send a married man away from his wife for a period exceeding four months.
In short, the husband should first let his wife accompany him; if this is not possible, he should seek her permission and not be away from her for more than four months, while doing his utmost to decrease the period of four months as well.”