Husband is in kuwait on and off 4 yrs?

It could be many things and not necessarily cheating but could be a possibility. Just tell him how you feel at first and be open with him, about the whole situation. Then at the end of the conversation just say, that you just wanted to express how you feel, and thank him for taking his time for listening. That way he can feel comfortable and hopefully he will get open and say his side. It could take time, just be patience.