The Libertine (Taskill Witches 2)

His powers could save her from ruin, or guide her swiftly to it.   
Lennox Taskill is a dissolute rogue, a powerful witch who some say even trades his enchantments for profit when it pleases him. His only loyalty is to his coven, his disdain for humanity sealed by the searing memory of his mother burning at the stake. So when the wife of a wealthy landlord comes seeking his help, the beguiling Chloris Keavey unwittingly presents Lennox with his greatest opportunity for distraction...and retribution. 

By failing to produce an heir, Chloris faces a terrible threat: being turned out by her heartless husband. Now, she vows to get with child, even if it means surrendering her body-and soul-to Lennox's seductive magic. But with a witch hunt brewing, Lennox and Chloris are soon risking everything for their forbidden nights of ecstasy...and to protect the secret that could cost them their lives.

"Walker deftly spins a captivating tale that will have readers holding their collective breath until the last page is turned." ~ Publisher's Weekly