New to all this and need suggestions

I'm the non ADHD spouse.   We bought the ADHD Effect on Marriage book and we were both reading it.  It was very emotional for my spouse.  We both were amazed at how it seemed someone was watching us live our lives and writing a book about it!  I went on to read The Dance of Anger and found it very insightful.  My dilemna is that my spouse has not finished reading the first book and shows no signs of doing so.   Is there a way for me to ask him about it,  remind him or otherwise suggest he get back to it without him feeling threatened or judged?  I've adapted how I'm acting with him because of the books.   But now he seems to think everything is okay and he doesn't need to do anything else.   Actually, no, I'm sure it's just that he's moved on and has forgotten we were even reading it.  Help!  Pretty sure I'm going to sign us up for the live counseling in the fall but that's a LONG time from now.  I know that any change he makes has to come from him.   But what do I do if he makes no progress towards that?