I echo what others have said, don’t move out, get legal advice, it doesn’t have to be fractious.
There will be surprises to come, I am sure people don’t break all the news and don’t be shocked if other things come out along the line.
A plan sounds good, but don’t be dictated to, if she wants to seperate and has already talked about where the children will live then I assume she wants you to leave.
You say she is happy for you to have the kids 3 days a week, I would expect her to be working those days, can she? How is she going to afford things?
She can’t force you out of your own home, she can legally change the locks, and you can legally break in (repairing damage at your cost). If she want’s a plan, then that plan has to involve you rehousing yourself and she needs to explain how that is possible.