XcalliberGhost

I have a theory about the plot twist.I think the master mind behind the marriage is the prosecutor groom.I know it is wild ,but if you put him into equation ,all the situations are suddenly possible.
1) The Phone call that FL got while drying ML's hair--
She yelled at the caller that she wouldn't back down 'it' like it is some 'deal' and she confirmed that the caller should keep the 'promise'. What's this 'promise' about?
And ,as we know FL was unaware that her family and step father il doh all knew about her relationship with ML.So the only possible figures are Prosecutor yeom and his uncle and she couldn't have yelled at the uncle for sure.
So , the prosecutor groom would have made a deal with the FL that she would have a contract marriage like thing,and she shouldn't tell anyone about it, especially ML as the prosecutor groom has a knack to irk ML and to degrade ML.The prosecutor groom knew about FL and ML's relationship and wants to devastate ML.As we know the groom is far from innocent.
In return,the prosecutor groom would help FL to solve her Dad's murder case.The 'promise' may be the deal and to keep ML safe,not to expose him to danger.

2) The FL has only made a deal.In reality she loves the ML only.As in the bathtub scene ,she was confirming the feelings and future actions of ML.
If she had to betray the ML blindly for the case ,deal or money,why would have she asked about what the ML would do and gave him a pre -cognition.She would have just straight up betrayed him without confirming his future actions and felings.

3) We cannot see any intimacy between FL and the groom, because there is nothing to start with.They have married only on a 'Deal' and the Groom is not in love with FL.Its only a facade.Also this deal ,benefits Yeom family and step father iL doh.
Also,this makes the Decision of FL to 'not use protection ' during her intercourse with ML ,a possible move by her to cling to ML with his child and she would get a child to show as proof of marriage.

This plot twist makes all the incidents till now plausible.Also there was mention of a dispute between ML and prosecutor groom back in highschool.That may be trigger.
But, ML is the most pitiful character and from his pov it's still seems a betrayal by lover and everyone is against him.
So, he should go feral and turn the tables so that everyone who let him down would regret and atone.Still the FL could have given him some hints and made a plan with ML, so that she could have gained a valueable partner and ML wouldn't have been devasted.

Also ,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.

Also ,there was no intimacy shown or even depicted to happen between FL and the groom.There was no kiss at wedding , and even on the wedding night ,the groom was present with drunk ML.Btw ,the groom seems a simp and pushover. So ,I think so too that FL got pregnant with ML's child.

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.