Torrent of Tears by J.L. Madore

With her birthday approaching and her adoptive family angry with her, Lexi doubts her place in her own life. Where had she come from? Where did she truly belong? When her identical twin emerges from the surface of a frozen pond to reclaim her, Lexi abandons the security of Haven to go find out.
Unfamiliar with the customs, laws, and obligations of life in Attalos, Lexi’s warrior habits and acerbic wit clash with everything in her oppressed homeland. At odds with her mother, the royal guards, and her arranged betrothed, Lexi finds a reluctant ally in Rowan, shunned Noble of the Fifth House.

Through their sexually charged pursuit of freedom, Lexi learns that family and love are two very different things.