A Kiss of Fate by M.J. Putney

Laird of an ancient, powerful Scottish clan, Duncan Macrae is committed to ending the ceaseless strife between Scotland and England. But he also has other, secret powers—those of a Guardian, humans with mystical abilities to control nature’s forces and see into the hearts of others. And from the moment he encounters the young and independent English widow Gwyneth Owens, his fiery spirit is irrevocably drawn to claim her as his own—a passion that will not only set his loyalty to his land against his sworn Guardian vows, but will also threaten everything he cherishes most.
Though Gwynne’s father was a Guardian, she believes that she has inherited only her mother’s beauty, not her father’s power. Then one kiss from the dangerously alluring Laird of the Macraes ignites a hunger that shakes her to her soul—and reveals visions of a looming catastrophe that threatens England and Scotland both. Only by becoming Duncan’s wife, and ultimately betraying the man she loves, can she avert disaster.

As destiny and two mighty nations clash, Gwynne and Duncan must push their powers and passions beyond the most forbidden limits if they are to save their love—and secure the future.