You have taken a brave step and in my opinion the right step for both you and your husband. At this point he really needs to be seeking help. He can’t put the past right and it is pointless dwelling on it, what you need is for him to move forward and he can only do that by seeking proper help for his addiction.
My partner struggled with addiction and eventually it split us up and we didn’t talk for many years, however he did eventually come back much changed as was I. Spending the time working on ourselves and fixing the problems we seperatly had ultimately fixed our relationship, turned out though we had to go through that process apart before we could be together.
Spend this time apart building and/or maintaining a life for you and your children, try not to put time scales on things, it is about what changed not how much time has passed. If he is commited to his recovery and your relationship is a good one things will fall into place as long as you are committed to yourself to and wanting your life to be the best it can.
I understand what a difficult time you must be having and I will be thinking of you. Lily x