I think most of us would feel broken inside if we felt we couldn't tell our closest people. In time, I believe you will be able to talk to him and he will be able to hear you. He has before. He has been a great support, as I recall. In any event, try not to be resentful of him, to scapegoat him. Why? It used to be when I was hurting the most and felt most vulnerable, I would distance myself from the very person who was my greatest support. Like a wounded animal
I wonder if your husband feels torn. He may feel if he mentions the elephant in the room it will be harder for him and for you. Kind of like out of sight, out of mind.
Or he may feel he is protecting you. He knows how your son has hurt you and he just can't bear that you be hurt more.
Or I wonder if your husband is signaling to you that HE can't bear more.
I agree with the others that Nar Anon would help YOU. You would get it out. And get support. All the toxic pain, as time goes by, will seep out of you, and not into the rest of the family.
YOU DO NOT DESERVE TO SUFFER.
Your son, as usual, is showing little or no regard for you or anybody else. Oh. I get it. I do. But can you find a little bit of anger towards him? He deserves it. And I swear you will feel better. Right now you are turning the anger against yourself. I know this is so.