My Lord Segundo — Amii Lorin

Jessica Randall was a child of the West: she could ride like a man, though she was all woman. The rugged Wyoming Territory was her home, and nothing infringed on her independence -- until Duncan Frazer arrived. This man they called Segundo had spent years in exile and was captured by Jessica's allure. Without revealing his secret identity, Segundo fought to possess her -- and win her heart. Western Historical Romance by Amii Lorin writing as Joan Hohl; originally published as Silver Thunder by Dell