Peterson, Tracie. Heart of Cheyenne #1

"The heart finds its way when one least expects it--even in the most unforgiving frontiers. Invited by a friend to trek west and help establish the newly formed town of Cheyenne, Edward Vogel is prepared to leave the haunting memories of his wife and son's deaths behind him. The only problem is the corrupt new railroad town wants family men who can establish law and order, and desperation leads Edward to his friend Marybeth with a proposition of marriage. After her father's death leaves her with no means of support, Marybeth Kruger is in danger of having her two-year-old half sister taken from her. So when Edward Vogel, the widower husband of her late best friend, offers her a marriage of convenience to escape both their troubles, she has no choice but to accept. Life in Cheyenne is fraught with danger, but will this arrangement be enough to save Edward and Marybeth from the pasts they tried to escape? Or will life with each other put them--and their hearts--in more danger than ever?"--