Complex sentence: Sadie soon changed her mind, for the sake of her marriage, but Sadie's obvious contempt for her husband and his concern about her constant attempts to break up Tom and Charity drove further wedges between them.
Split into simpler sentences: Sadie soon changed her mind, for the sake of her marriage. Unfortunately Sadie's obvious contempt for Jimmy and his concern about her constant attempts to break up Tom and Charity drove further wedges between them.