As you listed Sir Walter's bad points, I thought of Elizabeth. She's no fool and although she's been allowed to take her mother's place in society and obliged to shoulder the responsibilities as mistress of a large house, she must know that it's because Sir Walter needs a handsome female to fill that gap.

There is no indication that he is her confidant. Where does Elizabeth turn for comfort and advice? And what would happen if he were to remarry? I just read a tale from reality where a young daughter who had spent some years by her father's side, was completely dethroned when a new wife appeared in the house. The daughter was more or less asked to return to the nursery.
By this time Elizabeth must also resent the fact that one sister is married and the other has been engaged. Where does that leave her?