Masquerade: Venice by Lisa Marie Rice

Ten years ago Cal Burns lost the only woman he’d ever loved, Anya Voronova. He had a ring in his pocket — and then she walked out of his life and he never knew why. He moved thousands of miles away, built an empire, became rich and powerful.
She broke his heart when he was young but he doesn’t have a heart to break now.

Anya Voronova has spent ten years working toward the Accords — a once in a lifetime chance at lasting peace in the Middle East. The Accords will be signed in Venice during Mardi Gras. The city is an explosion of glamour and joy — and then she comes face to face with the man she was forced to brutally leave ten years ago and has never forgotten. Cal is now powerful, rich beyond belief — and angry. She doesn’t care, just one last look at him will have to be enough to last her the rest of her life.

But Anya knows things that a shadowy group of men will kill to keep secret. And when they come for her, Cal discovers he has a heart after all. And it belongs to Anya. It always has.