I don't think you should try anything right now, until you've at least learnt how to stand firm and not let your partner trample all over you. Keep in mind that it always takes two hands to clap in any relationship so it's never completely one person's fault only (even if she tells you so). Unfortunately, as long as you remain like this, she is going to always take advantage of you no matter how many times you get back together with her and she may even think less of you each time. Learn to respect yourself first, if you want to win her back and have her eventually respect you as a partner.
In your case, keep NC shorter than 30 days - usually, around 2 weeks would be enough. Reach out but perhaps you might want to consider all the angles first before deciding whether to tell him or not about your addiction. Some people might take it the wrong way and instead of even feeling pity, it pushes them further away because technically, you weren't being honest throughout the relationship. It might be better to come across and tell him that you've changed and leave it at that unless you know for certain that he would be understanding towards your situation.