Big Sky Country by Linda Lael Miller

The illegitimate son of a wealthy rancher, Sheriff Slade Barlow grew up in a trailer hitched to the hair salon his mother runs. He was never acknowledged by his father–until now. Suddenly, Slade has inherited half of Whisper Creek Ranch – one of the most prosperous in Parable, Montana. That doesn't sit well with his half–brother, Hutch, who grew up with all the rights of a Carmody. Including the affections of Joslyn Kirk, the homecoming queen, rodeo queen and beauty queen whom Slade has never forgotten.

But Joslyn is barely holding her head up these days as she works to pay back everyone her crooked stepfather cheated. With a town to protect – plus a rebellious teenage stepdaughter – Slade has his hands full. But someone has to convince Joslyn that she's responsible only for her own actions. Such as her effect on this lawman's guarded heart.