husband is an addict

Just discovered that my husband has been hiding his addiction from me yet again! The 1st time I went 8 yrs without knowing he was a meth addict. I thought he was clean and had been for almost 5 yrs (minus a handful of relapses), but I just found the truth. I am not sure how to handle it. I'm so angry about all the secrecy. It has been making me sick to my stomach thinking something was going on but having no proof and no way of knowing for sure. Now I know and face myself with a dilemma....do I stay or do I go? He is a functioning addict and we have had no problems other than him hiding this from me. Obviously, he does so well on it that I had no idea for 8 yrs!! But I cannot handle the lies and secrecy and I don't know if I can handle the truth either. Obviously, he is not going to stop doing it. Honestly, our relationship is so much better when he isn't sober bc he is much more happy than when he is struggling with recovery.

UPDATE: my husband admitted to using ICE everyday for the past 6 months. He tried stopping cold turkey and couldn't handle the withdrawals. He is trying to wean himself off now and if he is unable to do it on his own, we are going to look into detox centers.