Compare Twin of Fire (Chandler Twins Duology Series #1)

Jude Deveraux entwines the frontier adventures of two unforgettable sisters—demure beauty Houston Chandler and her independent, hot-tempered twin Blair—who discover heartfelt passions as powerfully and compelling as ice and fire... While dreaming of practicing medicine, Blair falls in love with her placid sister's fianceé, himself a doctor. Blair's impetuous spirit has won her a medical degree in a man's world—and captured Lee Westfield's heart. But even as the couple's ardor grows, there are nights when Lee disappears only to return exhausted, haunted. His silence imperils their love—but the truth would imperil her