Child Acting Out in Father's Absence
Your son is reacting to the change in your family dynamic. The first step would be for you and your spouse to acknowledge that your son is having a tough time adjusting and accepting this change. You both need to sit down with him and discuss the issues at hand in an environment in which he will feel safe and comfortable.
Allow your son to use words and draw pictures, so he can communicate his feelings and thoughts about what is going on in his life. It is also important for him to be able to ask questions.
If possible, make sure that he understands not only why you are having this talk, but also the issues surrounding itthat his dad's new job and extra work hours mean that your family will be better off and will be able to do more things. It is also important to validate his feelings and accept that he is acting out because he feels confused and scared. Ask your son what will make him feel better and then work with him to meet his needs, compromising with what works for you as well.
After this discussion, your son should understand that his world has changed and he will begin to accept it. He needs to be able to connect with his dad like he has in the past. As a family, you can figure out ways your son and his father (as well as the entire family) can spend time together in order to alleviate the feelings of not having dad around like before.
Also, talk to your son's school teachers, coaches and other leaders from the social outlets that he is a part of to make sure that his "acting out" behaviors are not spilling over into other areas of his life. This is a good forum to begin to address these problems and any conflicts that arise from them.
When discussing these issues, be sure that you and your spouse work together to show that you are a united front. Dad must show that he does care and loves his children. Help him figure out a way that he can spend more time with your kids, as well as the whole family. And also, set aside some special time for just you and your husband!