You say your daughters don't see or hear you arguing or being sent to your room because they are in their own rooms.
If we have an argument and my husband tells me to go to our room it helps due to giving us space. I realise that may not be the most healthiest way to do that.
You're right there. He's controlling you. It's his way of winning the argument by sending you away.
You are not a child but he's treating you like one.
Kindly, I'd say they do know. Children see and hear a lot more than they let on. They pick up the atmosphere. It doesn't have to be full-on shouting or physical abuse.
Yes, he tells me to go to bed pretty much every night but the kids aren't around then.
Why? Because this is his weird way of controlling you? It's emotional abuse.
If you go to bed because your H has told you to, as he doesn't want to argue or discuss things with you, they will know. There will be a pattern.
Maybe you need to ask yourself why you comply with this?
You don't have to go to bed when he tells you to.
What happens if you refuse?
The sad thing is you are still in an abusive marriage. But you can't or don't want to see it. He may not be abusive like your first husband, but you are still with an abuser.
I posted a link before to women's aid and their page on 'what is abuse'- might help to read it and call them for a chat?