Kdrama, FL with a secret

I would like a kdrama where the female lead has some kind of secret that she hides from the male lead, but he discovers it very early in the drama and pretends not to know in front of the female lead — let's say because he thinks if she knew he knows she’s going to distance herself, or he finds her attempts to hide it cute, stuff like that. I would like it to stay in that state for the majority of the drama. Does a drama like that exist?