The Time Traveler's Love by Lavinia Roseknight

The world Lena lives in has been at war for five years now and heading towards certain destruction. It's all thanks to Damian Judeson, known as the Destroyer: a General who wages war over the entire continent. If he isn't stopped, prophecy says he will rip the fabric of magic apart, and then the world will cease to exist.
Lena's special ability is being able to withstand time-travel. To prevent the Destroyer from being born, she goes back in time to before he was conceived. Her goal - to assassinate the Destroyer's father, Jude.
However, Lena doesn't want to be a killer, and Jude is a kind, innocent man. Unable to bring herself to end his life, Lena tries to exist in the peaceful world of the past while suffering from post-traumatic stress disorder.Will she find another way to stop the Destroyer from being born?
Trigger warnings: war, post-traumatic stress disorder, suicide, tragedy