Stolen Vows by Stephanie Sterling

For as long as anyone can remember, the Camerons and the MacRaes have been involved in a bitter feud. That feud seems likely to continue when, while delivering an ill-timed olive branch, Laird-to-be Roan MacRae encounters Isla Cameron stranded on the side of the road. He stops to help, and is quickly trapped in Isla’s dangerous web of secrets.

Falsely accused of offending Isla's honor, Roan is given no choice but to marry the girl. He vows that he will never forgive his wife for her treachery, but that is a promise that his body and his heart may be unable to keep.