Where Duty Lies — Patricia Robins

The minute Charlotte sees Meridan Avebury at a wedding, it causes such strong, passionate feelings in her heart that she believes it must be love at first sight. But Meridan is already engaged to beautiful Phillipa, who is dangerously ill. And while they don't deny their feelings for each other, Charlotte and Meridan are unwilling to take happiness at Phillipa's expense. However, Meridan becomes troubled by divided loyalties and struggles to find where duty really lies. How will they resolve their feelings?