Swan Prince

From Bamboo Garden:

Louri is a witch. She wasn't always a witch, however; an incident caused her to be this way. And a long, long time ago she cast a curse on her beloved which makes him turn into a swan for the daytime. The only way to get him back to the way he was before is a kiss from his beloved. Louri wants to help him become his true self, but her jealousy leads her to do the opposite- and destroy relationships.

Original Webtoon