Soul Food by Michelle Gross

With no choice, a human bargains her soul for ten years of music and song.
With no time for anything beyond her dream, Ruth Thomas becomes a worldwide sensation, never knowing love or appreciating lust until she finally meets the mysterious president of Black Hearts, Amit Kingston.
In a game of seduction, Ruth thinks she can enjoy a moment of lust, if only once, before the demon comes and devours her soul. Only the demon makes touching men impossible and getting Amit Kingston to crack is a job itself.
The demon doesn’t just own her soul. He controls every aspect of her life, including her fragile heart and her body’s desires.
Worst of all, Ruth doesn’t realize how close the demon really is.