The Magic Crystal: My Hated Wife is My True LoveEpisode 4

Abused by Duke Kaelen, Elaina fled after he faked their baby's death. Four years later, she returns as Grandmaster Potioneer "Nightshade" for revenge. Unknowingly, she bonds with her ex via crystal chat as confidants. When identities are exposed, she finds her son alive and Kaelen was manipulated by her stepmother. Remorseful, he shields her from a fatal strike. They reconcile and wed magically.