Hi and welcome to our side of the SR forum!
First of all, congratulations on your decision. For your relationship to have a real chance to work, you do need to be sober and emotionally available to your man.
That said, my response is simple. Ask him and honor what he says he needs, even if its not what you want things to be like right now. Don't make promises you can't keep. Be open with how hard this is for you. And let him know Al-Anon exists for him if he needs some support that you can't provide.
Prayers to you on this journey!
~T