My father got married to my stepmother three years ago when I was in college.
From the start, she mistreated me and my brother in every possible way, like sabotaging our possessions, breaking into our room, spying on us, and turning our father against us.
Five months ago, my brother and I got jobs and she asked our father to get money from us because she wanted to renovate the house, but my father refused. This matter got worse and my father divorced her, which brought peace to our lives.
But now my father is in contact with her again and they are planing to remarry. I told my father not to marry her. After his divorce, we told him he could marry someone else but not that woman again.
Yet now he is determined to marry her again. We tried to threaten him that we would leave him for good if he does this, but he blackmailed us with religion and said that this is just what he expected from such unfaithful children, that state law and religion permits him to do so, etc.
So far, what I have planned is to move to another city or rent a house, but still I cannot afford to rent a house with my current income.
I prefer that he either find some other woman if possible, or let us leave without blackmailing us. He is firm on marrying the same woman, and keeps saying that those previous situations won't happen again and he assures us this (I don't believe him and his lover at all).
How can I convince my father to let us separate and do our work if he wants to marry her again?