This is a list of things you must do before you you even speak a word about leaving. These will protect you, your children and your finances.
Back up your data
You must transfer and backup all of your data from all of your devices. Create a Google account and get an external hard drive. Transfer all of your files to the external hard drive and save them all to your new Google Drive. Remove the data from the devices and make sure you empty the recycle bin or trash on all the devices. Remove any other backups of the data from any cloud services for each device. Spend sometime making sure you have removed and transferred everything.
Change your passwords
Change every password for every single account you know. I would suggest creating a Google Sheet in the newly created Google account and store the passwords here.
Turn on 2 factor authentication for every account you have including the new Google Drive.
Manage your paperwork
Remove or shred all of your paperwork from the house, this includes bank statements, credit card bills, investments, bonds and wage slips. Copy anything you have joint accounts with your ex, photocopy where you can, but always back this up with a photo of the documents to serve as a timestamp.
Redirect your post
You should redirect your post to another address. If you have family or very trusted friends, not joint friends unless you can 100% trust them, their partner or anyone else that may go to their house in case friends of friends see your post there.
Record and report
If there are incidents that happen, record them, if needs be report them. If there are any threats or acts of violence report them to the police, or if they involve your children Social Services. Do not be scared, do not think you’re overreacting, if it is a real and clear issue then do not ignore it.