OP does he work?
Just wondering so we can help you plan how to reach out for support.
Are you due a smear test? I know as a parent carer mine is often left a little late.
Or ask GP to book you in for an annual health check up. They offer these for parent carers, tell him its a new thing.
Go to the smear test/health appointment and tell them you need help.
If he asks why you were there so long just say the appointment was running late.
Or if school have any parent meetings during the day while he is at work, go to the school meeting, and ask to speak to their safeguarding lead. Open up to them, tell them you need help as you've seen now that it is affecting your dd.
Be very careful with your phone and other devices to wipe any history (but leave some if you can so he's not suspicious, keep your usual history).
Another good tip is to make a brand new email address on a server you don't usually use. So if you usually use gmail, make a yahoo one for example. You can use this to email services for support. Make the password one you can remember in your head, but that he won't guess.
Look up local DV organisations in your area, look up your local police DV team, search for any services that might be able to help and email them.
I'm glad you have realised he will never change. Please be very very careful, but do start reaching out and making plans.