Reference: Fataawa wa Rasaa.il Mukhtaarah – Page 434
Question: What is the ruling regarding the absence of some husbands from their wives for a long period?
Response: If the wife permitted her husband to be absent for a long while, then there is no harm in him being absent. However, if she did not permit him, and requested him to return, then he is required to return. That is because it is befitting that he visits his family (wife and children) every four months at the [very] least. However, if this entails harm upon him, or if his circumstances necessitate his absence such as for earning a livelihood or that which is similar, then there is no harm in him being absent beyond this period [of four months].
And Allaah [alone] has the Complete knowledge [of all affairs].