XcalliberGhost

She has not cheated yet , She is intimate only with ML (physically,sexually and emotionally)and is not close to the pushover groom. She is only acting as married to let the enemies drop their guard. But yeah her actions and choices are sh*t and sociopath-like.Her betrayal towards ML is fully wrong. She herself doesn't know what she should do.She could've come clear to ML and would've gained a valueable partner in her quest .But No! She had to act out and betray ML.It may be to protect ML as per "the promise on phone call" or her plan to decieve the enemy(as the saying goes, ' to decieve the enemy you have to decieve your friends first').But she should get hurt the same amount , atone for her actions and grovel to get back to ML.Only then ML can forgive her.

And lastly,
Yoon Sang Hyeon is born to play brother-in law character of Park hyungsik.PSH always falls in love with Yoon SH's Noona 🤣🤣🤣,like in Doctor Slump.

I don't know what the FL is thinking?she could've explained everything to ML ,so they could've worked together for the cause!!!She is just straight up acting dumb.
Also, I think FL is just acting like she got married ,as we didn't even see her kiss the groom at the marriage, not even getting close to kiss,let alone sleep with the groom .And also as she was so possessive of the ML in the bath tub scene, she thinks of the ML as her only love, as she told thet she could die for him.So, she can't get intimate with others if she herself is that emotional and jealous of women getting close to ML.I think she would just act like married and maintain distance from the groom (as he seems like a pushover till now who is bad but is surrounded by a family of worse) while finding clue about her father's death(like a strategic contract wedding which is common in business world in dramas).But her motives are visible clearly.Also in the phone call after bathtub scene where she yells at the caller to keep the promise.Just what is this "promise" about and who was the caller.
On the other hand ,Our ML should destroy everyone who betrayed him, and even if he has to forgive the FL to act like married without consulting him,he should atleast show her the ropes ,so that she gets hurt as much as he was hurt and grovel to get back with the ML.
ML's motives are clear as day ,straight forward ,so he should go feral.
Btw ,screenplay was good , even in the 1st ep the ML and FL got so intimate that ,when the ML was hurt and crying that the viewers may feel the pain in the heart.The love scenes were acted pretty well and heartwarmingly,cute and romantic.That's the reason for the viewers for hatingthe FL so much .
Personally i was attached with the character of ML so much that ,the dialogue "I was confident that that I can win at both love and career success, but got defeated in both" ,I can feel his disappointment.It shows that everyone knew about ML and Fl but sidelined the ML and trampled over him as he seemed a thorn on their path to success.Now that he is alone , with no one seemingly on his side(the chairman is of business mentality ,so he would not be of much help and FL herself is confused about her decisions, brother-in-law Tahyeun has least power play and the bad prosecutor has yet to show true colours),he may reveal his darker side.