You say that you are afraid that you will over step your bounds, apparently you haven't yet because your boyfriend says you are to soft. Sit down with him, express your fears and ask him what he expects of you, how much of a part he wants you to take.

I'd hope that he expects you to have some kind of influence there as there may be times that you are left alone with the little fellow.

On another note, I know exactly what you are dealing with where ADD is concerned. My oldest child was ADHD, he was non-stop. We found that the best (or worst in his mind) discipline in lieu of a spanking was to make him sit still in a chair for a set amount of time when he got in trouble. Thank goodness he grew out of it for the most part - still has attention problems somewhat but the hyperactivity is pretty much gone.