The Return of The Long Lost Lover

Meliodas has a lover. No it's not Elizabeth. It's someone else. Dating back all the way 4000 years ago. His lover left to find a lost treasure. One that could seal back the demon king himself! She wanted Meliodas and herself to have a happy life together. And so, she left.

Now 4000 years later, with Elizabeth in the scene, how would she react?