Driven By Duty by Mia West

A warlord’s daughter has responsibilities. No one knows that better than Gwen, only daughter and political pawn of her father, Uthyr. But with her husband banished and her brother gone after him, Gwen isn’t leaving her fate in Uthyr’s hands one moment longer. She needs someone she can trust. Luckily, her lover Elain is the most courageous, loyal, honest woman she knows.
Elain has a secret, and helping Gwen run away will only bring them closer to exposing the truth: that Elain too is the daughter of a powerful warlord—and his only heir. Now her best chance to give Gwen a secure future is to reclaim her birthright. But doing so would mean confronting the father she fled years ago.

Meanwhile, Arthur’s restlessness amid the tedium of a winter border camp draws Bedwyr into risks that could inspire men to swear their swords…or destroy the tenuous alliances holding the Saxons at bay.