Why does Kate finally decide that she must leave her husband in the novel, Weyward?

Simon, Kate's husband, abuses her both emotionally and physically. He dictates how she is to dress and how she wears her hair. He tracks her using her iPhone. He began refusing to let her friends see her when one of them asked about Kate’s bruises. When Kate tried to leave Simon because he was being abusive, he lured her back home by claiming he had taken an overdose of pills. When she was home, he threw a cup of boiling coffee on her arm, burning it and leaving a scar. He forced her to quit her job after that and kept her as a prisoner in their apartment. Kate decided to try to leave Simon again when she discovered she was pregnant. She believed Simon would abuse their child just like he abused her.