Shotgun Bride (The Quinter Brides 1) by Lauri Robinson

Like most girls, Jessie Johnson will never forget the first time she met her mother-in-law. After all who can forget a shotgun pointed at them?

 Bartered for a dead horse at gun point, she either agrees to marry one of the Quinter boys or her brother will hang for horse theft. Jessie knows nothing about being a wife- other than the wedding will likely put her new husband in grave danger. After being knocked unconscious by his brothers, Kid Quinter finds himself surrounded by his uncouth family, the sheriff, a preacher, and an adorable young woman. Tied to a chair, he's given no choice but to marry Jessie Johnson. And that’s just the beginning of his troubles- it appears his pretty little wife has quite a past, including a notorious gunslinger looking for retribution.