It makes sense that he would start using suboxone a year after staying sober if he relapsed and didn't want you to find out about it. There is a lot of shame that comes along with being an addict. It's not something addicts are proud of.
My AH used suboxone correctly first, and then thought he could use it intermittently in between his highs. While he was using it correctly he wasn't acting like an active user. His behaviors returned (lying for no reason) and other little things only a wife would notice. Then he denied until he was blue in the face.. but at that point didn't believe him. There is nothing we can do to stop them, until they are done. Get out of the way. He will try and get you to stay, because i'm sure you make HIS life great. An addict can love you, but they can't love you more than their drug until they are out of active addiction. It's a very hard truth that I didn't care to swallow. My AH is in jail for his actions and hopefully will be attending a 14 month program for rehabilitation. I hope this will get him some sanity back. Maybe, I can have our family back... maybe not. We are all here together. Good luck.
I would like to add that Active addiction cannot hide forever. It will try. It cannot stay hidden forever. It will come out of the closet one way or another. It's not our job to "catch" them. I simply told him " I know your using!, If you act like a duck and quack like a duck but TELL me your not a duck and expect me to believe you - who is the real idiot!!" I left it like that and stopped making him dinner... and only made me and the kids food. ... Life as a wife of an AH is madness.