Every day you stay there is a day away from you starting to move forward. I know it is scary, but you need to leave, and soon.
Christmas in your house will be the next one. This is not your house, as it was, any more. If you feel like this now, Christmas will be a million times worse. And, you are both delaying the inevitable separation. He is the only person gaining from that. You are still cooking for him apart from anything else.
If he is ever, ever to start facing reality about his family (which is unlikely I'm afraid) it will only be with consequences. Alone in the house, no one to talk to, no dinners cooked or washing done, no nice cars to borrow and the prospect of Christmas alone.
But, and this is the crucial thing, you will be better off away from him. Because you will have taken control of your own situation as much as you can. Much of your misery atm is to do with you feeling powerless.
It will be difficult, at your DM's, without your DD. But still better than where you are. Why not do it. When he is at work, pack up, take your stuff, take the decorations if you want. And go. And don't tell him until you have down it! Make this a new start, both you and your DM.