Book Under the Oak Tree, Vol. 3 novel — Suji Kim

The day that Lady Maximilian has been dreading is here: after an arduous journey to Livadon, she must stay behind at a monastery while her husband, the renowned Sir Riftan, rides off to war with the Remdragon Knights. Fretting for their loved ones, Maxi and the other noblewomen in the monastery keep themselves busy tending to villagers in need at the local shelter.
But Maxi's patience quickly runs thin as she fears the worst. Desperate to see Riftan, she escapes the monastery and makes her way to the battlefield. Little does she know that the brutality of war is not the only danger awaiting her. As she confronts her painful past, the tumultuous present, and an uncertain future, Maxi faces the greatest obstacles of her life – and the gravest threats to her relationship with Riftan thus far.