I was in this position for 8 months and it was awful. Child is adult and has own home.
I had a separate bedroom and en-suite. I also had another room I could make use of that my husband didn’t use. I just kept to these two rooms as much as I could. I used to nip to the kitchen when I thought he wasn’t in. I ate a lot of omelettes because I could be in and out of the kitchen very quickly.
At his suggestion, we did our own washing and cooked our own meals. He pretty much lived as before and had the run of the rest of the house, (minus me washing, cleaning and cooking for him). He held bbq’s, and had people back from the pub for impromptu parties, and had friends come and stay. Many of these people were our mutual friends, but I just kept out of sight.
The worst was that he would just come into my ‘sitting room’ and berate and harangue me for wanting a divorce. It was fucking awful and I couldn’t stand the sight of him.
Unfortunately, I could not answer back - he would then just rage at me. He was emotionally abusive and was used to me doing as he wanted. By the time I left I was both mentally and emotionally broken.
I was advised by my therapist to put a lock on the door, but I never did as I was scared of his reaction to this.
If neither of you can/will move out then @EliflurtleAndTheInfiniteMadness has pretty much said it all. Get a friend/therapist lined up so you have someone to talk to. Gather up all your existing friends even just for fun and socialising. I didn’t and withdrew so I felt very isolated.
If you can, agree that you will tell each other when you will be away/out of the house. Then you at least can have a few hours of peace if he’s out say, job hunting.
I actually spent six days dog sitting for a friend in her lovely cottage in the country during a hot spell. That memory is a beautiful oasis during an incredibly hard time.
Im not sure if you can protect your mental health and not tell the children without giving the game away. You may have to think hard about this.