(((hugs))) Welcome to this site. I really encourage you to consider attending an alanon or a naranon meeting. It's a great way to support your husband - to find your own way of handling the addiction and learning how you could have been blind sided like this and prevent it from happening again. Just because your husband has to "do this alone" doesn't mean you should or you have too. Maybe it will inspire him to find a support group. I think that the support of other recovering addicts is key to recovering from addiction. I should know. I am one.
Keep reading and posting ok. And consider checking out a meeting... just to educate yourself.