Read The Baby Isn’t Yours Manga:
Kalia is a war hero and commander that put an end to the past war. But one day, she finds out that she’s… pregnant?! Of all people, the father of the baby is Simon Terroan, her best friend and archmage, whom she spent a single passionate night with.
Believing that Simon doesn’t want the baby, Kalia hides the truth of her pregnancy, then retires from her job and disappears more.. while Simon is away in order to have her baby. But the truth is that Simon has loved Kalia, more than anyone else. And so, the frantic search for her begins.