Half a Chance by Emily E K Murdoch

Frederick Chance, Viscount Pernrith, isn’t really a Chance. Not entirely.
The illegitimate son of the late Duke of Cothrom, he’s tolerated by his three brothers and ostracized from the best circles. His title is a pity gesture from the family that never truly accepted him, and his bastard origins mean no one in Society will take him seriously.

Particularly not the latest rose of Society…
Miss Edith Stewart, on the other hand, is rather sick of Society’s attention. Flourishing rose of the Season? What rot.
She’s far more interested in the forbidden. The edges of Society. Those to whom she should, apparently, not be speaking.