This drama is similar to fall in love as the female lead suffers from the same Multiple personality disorder and the male lead has do deal with her.

The female Lead is an Alien came from another planet that has fallen in Love with a male on Earth My girlfriend is an alien shares a similar concept to Fish Knows you as both of them are about Aliens from other planet.

My love from the ocean has similar stories exept that in My love from the ocean the female is a mermaid not the male

Although not the same language but similar stories exept the male us richer one in legend of the blue sea and the female is the mermaid