Rules for a Bastard Lord by Katherine Lyons

A bastard can protect a lady, but dare he love her?

Bram Hallowsby has spent his life knowing his place. As the duke’s illegitimate son, he’s carved out a precarious position serving society from its shadows. When he meets the newly-discovered granddaughter of the Earl of Cavener, he recognizes a woman who deserves better than the scandal of loving a bastard.
Maybelle Ballenger awakens feelings Bram has denied his entire life. Though he can protect her, guide her through society’s treacherous waters, and even warm her bed in secret, he knows he must never claim her openly. A bastard’s love would destroy her chance at the life she deserves.
But as Maybelle’s suitors circle and pressure mounts for her to make an advantageous match, Bram faces an impossible choice: step aside and watch another man claim the woman he loves, or defy society’s strictures and risk destroying them both.