Between Duty and Desire — Leanne Banks

Bound by a promise made to a fallen comrade, retired marine Brock Armstrong had no choice but to seek out the man's widow. Past conversations and shared letters had given Brock great insight into Callie Newton; he knew her every like and dislike, her every dream...and her every desire. Arriving on her door, seeing her in person, had Brock reeling. This Callie was even better than his fantasy. And it wasn't long before he acknowledged how deeply he wanted her in his bed...in his life...forever.

But, for a man of duty, Callie was a prize he dared not covet.