Hi, I'd also check with al- anon and see if they have any ways they recommend explaining things or any materials they can lead you to to help.
You are very brave. This is a hard thing to do. Ultimately, you're protecting your kids. Your boys probably have seen some of his addicted behavior--- and not liked it. They just didn't know why dad was acting that way. When they are older, they will better understand that you were trying to help their dad and protect them.
Give them lots of love and time to vent. Good luck. And I hope that your husband gets clean for the sake of you all.
Well done you stood up and were counted, tell them thier Dad will miss you all so much he will get help, then he will come home,he will know now you mean it,hopefully he will get the help he needs, surely his prescribing Doctor will know what to do to help him wean away from the stuff he has been prescribing,So I think you behave in an upbeat manner, speak well of their Dad, be supportive when you can, make sure they see him regularly it is a fact that children do better if 2 parents are in their life .Take the boys out fill their lives with outings and sports , the busier they are the better so their thoughts wont dwell on feeling negative. Good Luck, will you let us know how you are all doing,