HaBO: Gun-Wielding Mistress Ruins Baptism

You did it! We figured this one out! It is a truth universally acknowledged (by me for certain) that the Bitchery pretty much knows everything, and really, it's true. Scroll down to see the solution for this HaBO - and many thanks!

This HaBO is from Krishnaa, who is trying to find a romance she read a few years ago:

I am looking for a Regency romance I read in 2013. I don’t remember the author or publisher or any of the character names, but remember almost all of the plot. I remember that the book had a lot of improbable plot points, was high on crazysauce, and vaguely slut-shamey, but was deliciously well-written. Seriously, the UST had me watering at the mouth!

The hero is a Duke (or Earl or Marquess or Somesuch), but impoverished. He has an arranged marriage with a daughter (our heroine) of a rich man. Our hero is in love with the heroine, but she is scared of him because he is about ten years older. Before their wedding night, however, the hero is led to believe that the heroine cheated on him with his younger brother. The hero becomes very angry and vows never to speak to the heroine again. He installs her in his country seat and goes off to London with her dowry. Meanwhile, the younger brother is shipped off to the military.

Five years later, the hero is a very rich man in London, thanks to the dowry and some wise investments and hard work on his part. He wants to divorce his wife and marry his mistress. But the wife comes to his townhouse and pleads with him to give their marriage a second chance, to look respectable in the eyes of the society. She wants her younger sister to have a “proper season” and make a love match.

So…you can guess what happens next. Lots of “ton” related scenes and standard Regency romance fare – balls, opera, carriage ride, morning calls, etc. The romance between the younger sister and her suitor becomes a convenient background/parallel for the lead pair’s arc. The hero breaks up with his mistress and finally consummates his marriage with the heroine. When he sees the blood stained sheets, he realizes that she had never cheated on him. After some mild grovelling on his part, they declare their love for each other.

Then the jealous mistress shows up and tries to shoot the wife. Somehow, our heroine escapes. The hero and heroine have yet another misunderstanding (again involving the younger brother). The heroine becomes pregnant but loses the baby because she goes riding in the rain and slips and falls. She recovers, the hero grovels, and then grovels some more. Then a year later, they finally have a HEA with the arrival of their first child. BUT! The mistress shows up at the child’s baptism or something and tries to kill everybody. Again, she is foiled and the hero shoots her dead.

This book was a weird mix of slut-shaming and sex positivity. The hero’s mother takes a much younger lover when her husband dies and is shunned by high society for this, but the author portrayed her in a positive light. But, the hero’s mistress is also a widow and was depicted as a crazy slut.

I want to find this book because I think it may have been a part of a series. I want to read what happens to the hero’s younger brother.

How long is this dang book? That’s a lot of things happening.