Broken Faith by SF Benson

Sex, booze, and tempting humans.
All part of Theseon’s job as a dark angel. He’s kept plenty of souls out of Heaven, and is willing to keep it up. But then he meets Grace. She doesn’t fall easily, and is ready to walk out of Theseon’s life. Something about him tempts her—a woman who has her own dark secrets.
Their interactions draw the attention of the King of Hell. Ashmedai doesn’t like it when his creations don’t follow the rules. When you piss off the head demon, there are consequences.
Theseon must face his worst fears while Grace must overcome hers.
Is love enough to redeem a dark soul? Better still, can it erase dark beginnings and point to the light?