The Marriage Experiment by Laura Trentham

As an amateur lepidopterist, Adriana Coffey would like nothing more than to live a quiet life in the country and await Cyrus Shaw’s return from his grand tour. After all, an understanding has existed between them since childhood. Unfortunately, with Cyrus out of the country, a marriage is arranged with her detestable stepbrother.

Dawson Shaw, the new Earl of Westhorpe, would like nothing more than to grab his younger brother up by the nape and shake some sense into him. Adriana is intelligent, beautiful, and unappreciated by society and his scapegrace brother. But is he willing to betray Cyrus in order to fulfill his own longings?
Adriana feels like she has no choice but to accept Dawson’s offer of marriage. Unlike the charming Cyrus, Dawson is aloof and cold… or is he? Their marriage is proof that assumptions can be disproven. The attraction between them is altogether unexpected and new for Adriana. But will their growing connection survive the coming tempest when Cyrus finally returns?