The Husband Trap by Tracy Anne Warren

Here comes the substitute bride. . . .

Violet Brantford has always longed for the passionate embrace of Adrian Winter, the wealthy Duke of Raeburn. Problem is, he's set to marry Violet's vivacious, more socially polished look-alike twin sister, Jeannette. But when Jeannette refuses to go through with the ceremony mere minutes before it is to begin, soft-spoken Violet finds herself walking down the aisle and taking vows in her sister's place. Soon shy Violet is a high-society wife, trying to keep her real identity a secret while living out the fantasies of her wildest dreams.

Adrian thinks he knows exactly what he's gotten himself into: Jeannette may be flighty and, well, a bit self-involved, but she's the picture-perfect wife to carry on the Winter name. Yet this marriage of convenience brings the groom more than he bargained for when he finds his sweet, innocent wife surprising him at every turn. And though he never planned on true love, Adrian is definitely in danger of losing his heart.

This book is part of the "The Trap Trilogy" series.
Here are some other books from this series: