From Ch4: Being now in her twenty–first year, Maria Bertram was beginning to think matrimony a duty; and as a marriage with Mr. Rushworth would give her the enjoyment of a larger income than her father’s, as well as ensure her the house in town, which was now a prime object, it became, by the same rule of moral obligation, her evident duty to marry Mr. Rushworth if she could.

It seemed to me that if she could see from her father that it was not a "duty" for her to marry Mr. Rushworth, she would think more than fleetingly about being released from her engagement. And perhaps it's from getting Sir T's POV, but it seemed that he had softened and might even be persuaded to negotiate move opportunities to meet more respectable men. (But he must seem all gruff and unapproachable to his daughters.) I understand that what she is searching for is "novelty and pleasure" but how short-sighted! Having gotten a taste of what it could be like to have an intelligent man treating one with attention, someone might overlook the idea that every man who behaves like Henry Dashwood does not also have to be deceitful, and so there are other men worthwhile pursuing.