Im sorry to hear about your story, in this instance would like to say I ‘was’ the husband but I am in a similar situation and still working through my addictions.
I think first of all this type of addiction can go on for many many years unnoticed and unchecked, I think you have to give your husband some credit for coming clean about the whole situation. As Stillhopeful says, addicts can be great liars and very selfish so for him to confide in you and come clean is a huge step!
It will not be an easy road and there will most likely be slips along the way! in the vast majority of cases addiction can be linked to past trauma. There could be an underlying issue here that you husband has not disclosed to you! I myself was sexually abused and silenced as a child and as a result of the abuse went on to grow up as a very timid, shy and introverted person (I was very loud and out going prior). When I found cocaine and alcohol (as crazy as it might sound) I felt like for the first time I found my voice and it was an amazing feeling, it was like the drugs allow me to be the person I was supposed to be! Freeing me from the years of hurt and bottled up shame and guilt!
Cases of abuse are so prevalent that its difficult to comprehend the scale of this issue, now Im not saying your husband was abused, but there could be a variety of reasons that have caused him to go down this path, happy people do not self medicate in this way!
Try to be there for him and hopefully he can open up to you about exactly how he is feeling! Recognising feelings and triggers and learning how to cope with them will be the key to beating an addiction, again as Stillhopeful says if he is saying he is fine and its under control, for me from my own experience this is a huge red flag, as an addict in early recovery there will be countless times when the cravings are overwhelming and times when he may try to assess if he can get away with doing drugs without you noticing, these are the times he needs to talk to you and these are times you need to be there in a non judgemental way! Addictions do not just disappear overnight so these feelings will be totally normal try to embrace them with him and let him know its normal to still crave the drug, but its not ok to use!
One thing someone said to me that resonated with me quite strongly was:
Imagine your family and children on one side of a scale and the addiction on the other. Decide now which is more important! This imagine sticks in my mind every time I think about relapsing and I envisage my wife and kids high up in the air on this scale whilst the drugs are down in the gutter.
I wish you both all the best on the long journey ahead!