Get ready for lost wills, broody dukes, and scorching hot kissing all over London in Rules for Engaging the Earl by Janna MacGregor.  

Constance Lysander needs a husband. Or, so society says. She's about to give birth to her late husband's child—a man who left her with zero money, and two other wives she didn't know about. Thankfully, she has her Aunt by her side, and the two other wives have become close friends. But still—with a baby on the way, her shipping business to run, and an enemy skulking about, she has no time to find the perfect match. 

Enter Jonathan, Earl of Sykeston. Returned war hero and Constance's childhood best friend, his reentry into society has been harsh. Maligned for an injury he received in the line of duty, Jonathan prefers to stay out of sight. It's the only way to keep his heart from completely crumbling. But when a missive from Constance requests his presence—to their marriage ceremony—Jonathan is on board. His feelings for Constance run deep, and he'll do anything to make her happy, though it means risking his already bruised heart. 

With Constance, Jonathan, and the new baby all together, it's clear the wounds—both on the surface and in their relationship—run deep. But when the nights come, their wounds begin to heal, and both come to realize that their marriage of convenience is so much more than just a bargain.