Women tend to have a good sense when people especially men are hiding something. Usually it is a good sign that they are. Whether it is good or bad you def need to talk to him! I have learned from past experience that you may or may not want to hear what they have to say, but if you are losing sleep you need to find out. It may very well be something that had nothing to do with your relationship, and he may really want you to ask about it. You will never know till you talk about it

Best wishes
Ashley