You could ask your landlord for another tenancy in another property , though that woulod need savings as you would probably not get the full bond/ deposit back if your partner remained in the property you share now.
If he is the registered father of your children you need legal advice anyway. Start sorting out an escape plan, donl;t do anything in a hurry, even if the children seen agitated, thye can be at school most of the time. Ask at your local CAB about refuge and support in the meantime.