If the Viscount Falls by Sabrina Jeffries

Image linked from Goodreads

Possibly my favorite story of the series. Dominic Manton arranged it so that he would be jilted by Jane Grey. His brother had disinherited him so Dom knew (oh, you foolhardy male) that Jane would be better off without him. But now George, his brother, is dead, and Dom has ascended into the title. Jane is newly engaged, but she still comes to Dom for help when her cousin disappears. The cousin who was married to Dom's brother. The cousin who helped orchestrate the jilting.

The cousin who might be carrying a baby that will disinherit Dom.

Great character development between these two. No Big Misunderstandings. And, yes, some of these could have been solved if they just talked, but a lot of it was gaining maturity.
This book follows How the Scoundrel Seduces, it comes out on January 27th.