It won't be easy but their madness dies down.
I think it is harder than anybody could ever imagine, because once you leave, there is no pretence that you're a team. Once you reject them, they will TAKE YOU DOWN.
So make sure you have somewhere safe to go.
The administration and the practicalities of leaving can be hard when you're already feeling depleted and lacking confidence in yourself. But once they are behind you and you're safe, then you can start building yourself again.
He almost certainly will tell you he's going to go 50:50 and he almost certainly won't really want that. If he tells you hes' going for 50:50 do not respond, get your solicitor to say fine. Tell him you look forward to having half the week free and don't discuss it further.
Money was tight for me for a few stressful years but I was listening to endless clips on youtube about self-esteem, family systems, resilience, emotional intelligence.
I NOW, 13 years later, feel that I am living with far fewer blind spots, resentments, fears, doubts, anxieties. I am less of a people pleaser, I'm more resilient now, less of an over-sharer, my locus of validation is more internal that I could ever have hoped. Thank God I left him. It really was character building.
Keep posting. So many people have been in your shoes. It's a terrifying time. YOu have to emotionally take a huge breath and swim underwater until you come up for air, safe. It's not easy, but it's worth it.