The Officer and the Bostoner (Fort Gibson Officers #1)
Rose Gordon

Given the choice to either temporarily marry an officer until her intended can come rescue her or take her chances with the indians, she marries the glib Captain Wes Tucker, who unbeknownst to her, grew up in a wealthy Charleston family and despises everything she represents.
But when it's time for her beau to reclaim her and for Allison and Wes to annul their marriage, will she want to go with him, and more importantly, will Wes let her?