Right now he is on an emotional rollercoaster. Drugs surpress emotions, during active addiction the addict is numb, if clean, he is now having to face these emotions. So, I wouldn't expect too much support from him. What about talking to your friends or family members about your feelings and concerns?
As for whether he has used or not, I do not know and nothing will be accomplished by confronting him, he will lie.
Keep in mind that this is his recovery, he is totally responsible for it, you are not. Your responsibility is to get yourself healthy.
Also, have you considered limiting your conversations with him? Like keeping it to one conversation a week. It may help you to start detaching and allow you to do more work on you, obsessing about what he is doing is not going to help you or your relationship one little bit.
Try and focus on you, keep posting, it will help.