The Binding Stone - The Djinn, #1

A thousand years of servitude left Leela more than a little jaded. The betrayal of the man she loved was only the beginning of the nightmare. After centuries of abuse by greedy masters, her hope for freedom for herself and her fellow Djinn from the magical stones that bind them has dimmed to a barely-there glimmer. But it hasn't yet been extinguished. When the young, handsome, and idealistic Jered inadvertently becomes her new master, Leela wonders if his tenderness and concern may be real.
He doesn't even realize that he's a magician and wields magic of his own. Despite her years of suffering, her heart begins to open to him. And the chance of romance. As she inches closer to trusting Jered, the original masters she assumed long dead resurface. They've found a way to survive, using young magicians' bodies to hold their essence. And when they discover her whereabouts, they come for her-and Jered.
If the evil ones succeed, then she'll once again be in the service of the man who betrayed her, this time forever. In the past, her choices led to unimaginable suffering. Now, when freedom or an eternity of torture both loom as real possibilities, can she dare risk everything for love?