Never Doubt My Love (Harlequin Romance, No 3146)

the long version

Cassie had put the past behind She'd jumped at the chance of nursing Lincoln Snow. After all, the now prominent stockbroker had once been the object of her schoolgirl dreams. Gradually, under her care, Lincoln was soon on the road to recovery and the bond forming between them seemed unbreakable. Then his evil nephew Tyler stormed into their lives, churning up memories of Lincoln's dead wife, Magda. That was when Cassie realized her only competition was the devastating power of the past.