You're not stupid, and it's not your fault. I don't think anyone here would blame you.

Have you tried contacting a domestic violence hotline or shelter? Even if you're not able to leave him yet, they may be able to help in other ways. I wish I had more ideas to offer, but I've never been in your exact circumstances. But I do know that it's not your fault, and you don't deserve to be treated that way. You shouldn't have to live like that.