I normally love stories where either the hero or heroine are under pressure to marry for society sake or for financial reasons. I love second chance stories. However, this did not jive. His mother threatened to inherit him??? Really?? Women had precious little power during those times. Sure, if her hubby, the old Duke made her the guardian of a young male child, she had some powers. If she was really lucky, her late hubby gave her control over her dowry and whatever else he chose to leave her, but late hubby could not give her control over the dukedom and the rest of whatever was entailed.
Therefore, there was no way, mother dearest could have disinherited her son completely, nor could she have taken his title. She could not even petition for the latter as legally, she really had no standing at all. She could have made her son's life and that of the heroine unpleasant at most, definitely if she was one of the Grand Dames.
I am not yet sure how the rating system works. The love story was cute, the interfering niece a little bit a nuisance but the love story was centered around the fact that the hero had absolutely no choice but to brake his engagement to the heroine and eventually marry someone else. And that was plainly historically untrue.