Healing My Wounded Hero by Monica La Porta

in an otherwise dull existence is when the daughter of the earl summons him—she is the object of his forbidden desire, the woman he can never have, and the reason he hates being a nobody.

Lady Charlotte, Charlie, is not on the shelf yet, but the clock is ticking and she needs to elect a suitable husband. She is not looking to marry for love as her friends have done—any lord with the right attributes will suffice. Namely, the man she will marry must show an interest in spearheading her many programs for the poor in the House of Lords. Nothing less will do.
That all changes the day she asks the new groom to escort her on a mission to save a child and her plans for the future crumble before her eyes. What starts as an infatuation soon becomes an all-consuming passion burning bright and fast until it is a fiery love that threatens to consume everything in its path.
He is a servant. She is a lady.
How can they pursue their hearts’ desire when society has decreed they can never be together?