You are an adult and are allowed to do whatever you want, as long as you aren't breaking the law. Only you can give yourself "permission."
You're not an addict, your husband is. Both of you are adults. All actions have consequences. It seems that one of the consequences of you partaking in drugs and alcohol is that your husband will try to use it to score points against you. He is telling you that he doesn't have to quit because you are not an addict. A-Logic at its finest. It's up to you what you do with that.
If your husband was actually making the slightest effort to recover and asked you to refrain from drugs and alcohol, I probably would respond differently.
But I'm guessing that isn't at all what's happening here?