Physical abusers do not stop. They try to make you feel trapped, like you can't escape, using weapons like the "loyalty oath" he made you take.
Newsflash: oaths made under duress are NOT BINDING. You owe him nothing. Make yourself safe--use this window to get out NOW.
You can deal with the grief and feelings of loss later, when you are safe, with the help of a therapist. Your life and safety come first.
However hard it is, do it.