I wish you had thought to ask someone this question twenty years ago before the damage was done. There’s not a lot that can be done for your son now.
I don’t want to berate you–what’s done is done–but I have to be completely honest here, because it is important that you understand your part in this. You should have acted long ago. You had twenty years to do something about your husband’s abuse of your son, but you didn’t. You had 7,300 days to intercede; why didn’t you? Why didn’t you stop it when he was four, or seven, or twelve, or fifteen? Now at 24 he’s having problems–no surprise there–and suddenly you want to help? Did you not see this coming? What did you think the constant mistreatment would do to your son’s psyche?
Kudos to you for wanting to help him now, but it’s too little, too late. The time to act was before his self-worth was dismantled day after day by your husband, and before the self-image of a loser was seared into his brain. You seem to blame your husband for doing this, but to me you are just as culpable, if not more, for letting it happen. He is your child, and you should have protected him. Children are supposed to come first. You failed him. I’m sorry to be blunt, but you did.
There are a couple of things you can do now that might help, though. One is to tell your son that you’re sorry you failed him for twenty years. He needs to know that you realize your part in this and regret it. Then you need to get him some therapy. It won’t fix him completely, but it will help. Find him a shrink, pay for his sessions, and offer to go with him, too, as I’m sure he has some issues with you not standing up for him against his stepfather. Whatever else he needs from you to heal, you need to provide. It’s the least you can do.
I know you love your son, and I’m sorry to beat you down. The truth hurts sometimes. But your willingness to help him now is something. It’s a start. Who knows, maybe he can heal more than I expect. For that to happen, though, you have to make him a priority. You have to make this journey with him, however long it takes. You weren’t there for him before, so be there for him now.
Good luck. Thanks for the question.