The only thing that's similar is the basic plot of a struggling actor gets hired by her friend to be his wife to hide the fact that he's gay and that his younger brother tries to break them up. That's pretty much it. Everything else is different. 

Of course this is not me complaining. I actually like almost of the changes they have made. (A bit on the fence with the chaebol nonsense and the addition of the SFL). 

So asking for spoilers is basically useless, lol. 

ikr i just started reading the webtoon and i was like...yo this aint nothing like the drama?? I kinda like the webtoon more atm though i have only seen half of it so far....

what a shame but they told me how JH finds out his brother is gay, if they changed the way he finds out I'd be happier.

No doubt webtoon is amazing with perfect story, But i don't think drama is that bad, I am glad they didn't follow the whole webtoon,  A webtoon with 72 chapters they can't cover all the good and charming plot in 12 episodes. Even for a great screenwriter, it's impossible to cover an entire webtoon in 12 episodes....