In the short term, I would stop allowing him to paint himself as the victim and you as the person who stops him doing things. eg
him: 'I want to buy that car'. You: Great idea, I think you should'.
him: 'I want to have my own flat'. You: 'Fair enough, I understand. Go for it'.
He can't accuse you of stopping him if you're supportive, and it will make clear that it's only him stopping himself doing things. If he raises it again you can remind him 'oh yes I thought that was a great idea, what have you done about it?'. Even remind him proactively: 'Have you test driven that car you're buying yet? Exciting getting a new car isn't it'.
Make it impossible for him to claim you are controlling or stopping him being happy.
In the medium / longer term, I couldn't live like this. He will continue to drag you down, and your DC too, and at the end of the day he will blame you. If you split now, better for you, better for your DC, and it will show your husband he has noone to blame but himself.
I think I'd approach it as 'I know you aren't happy. You don't like being with me. You don't want to do anything fun with me. You see me as a barrier to your happiness. I think we should split. It would be better for all of us as your moods are bringing the whole family down'.