Sorry that you had yet another bad conversation with your H. It does sound like he is currently incapable or unwilling to step up for your S, so it's now on you. (and has been now for a while...)
I like the idea of talking to him with the C. Not only to help your S process it better, but also for you - to have someone be there to support and help you should you need help. This is all new territory for you as well.
Hang in there - you are strong and will handle it well.
Me & H: 44 D7, D6, S3 Together: 20y, M: 17y EA: 11/13/10, Sep: 12/23/10 EA becomes PA: Spring 2011 H filed for D: 09/06/12 D Negotiating began 2/15 OW seemingly gone on 3/15 Still negotiating D