Guardians of the heart / Loree Lough.

Enhanced descriptions from Syndetics:

Nell Holstrom wanted no part of her grandfather's barren gold mine that had taken the lives of her mother, father, and younger brother--even if there may still be hidden wealth inside. Instead, she went to Denver and took a job as housekeeper at the old Stone Hill Inn.

Asa Stone was barely more than a boy when his father dragged him and his brothers to fight with Colonel John Chivington. But Asa refused to participate in the raid on the peaceful Cheyenne and Arapahoe--and when the smoke cleared, his father and brother lay among the slaughtered. Besieged by guilt, Asa wandered the West for years before returning to Denver to rebuild the old inn he'd inherited.

Together, Nell and Asa work hard to restore Stone Hill. But when disaster hits the inn, Asa retreats into despair and Nell is forced to return to her family's mine. Asa faces the hard fact: He'll never be the man Nell deserves. Can he overcome the dark secrets of his past? And will Nell still love him when she learns the truth?