Actually, @ragingloli is the closest answer here to best advice.
What you need is strength, but not necessarily muscle mass.
I think the biggest fail the women’s shelters have, is not educating women in the things which will best help them to survive without a man’s help.
YouTube can provide a lot of that now.
Anyway, inner strength is what is needed. Anger is not always the reason for leaving a S/O.
Disappointment, lack of trust, lack of affection, lack of most any type of nurturing is not only the most common reason for wanting to leave a relationship, but also a common reason for being afraid to leave. If I. Can’t get _______ here, can I ever find it somewhere else?
So inner strength, recognizing what is holding someone back from leaving, and finding that within theirself is the necessary strength to successfully leave.
In short, recognize that this significant other is insignificant, and walk away chin up.