So is it normal to be engaged to a mentally challenged man? Did she cheat on him with his brother???? 

I dont recall any scene implying that she cheated on him with his brother. if there was such a scene that made u think that way please remind me. i dont think she has any reason to cheat on him bcz if she doesnt love him enough then she wouldnt get engaged to him considering his disability right? if she liked the brother then no one is forcing her to marry the disabled one right? so no need to get engaged and then go behind his back as he is not some rich guy. 

and is it normal to be engaged to a mentally challenged man? well it maynot  happen often but we see odd couples all the time like there may be huge age gap or other kind of disabilities. for example, she might have had trauma with other men that she finds him safe,  just a case. many reasons for her to choose him. 

the scene when they kidnapped the real judge!gotta look it up  again i guess

However, there is no way any court worldwide to approve this marriage he was mentally challenged not physically

court wont approve? is that true?

Because mentally challenged person doesn't have good judgment skills also he cant choose 

even if its only for sex when the person is retard its like taking advantage of him, in this drama the dude cant understand his grandma is dead ffs

i see what u mean, any way if they had an affair they would have atleast stayed together in the end right

yeah,the whole story of the fiance' dosnt make any sense 

 Lustdrama:

So is it normal to be engaged to a mentally challenged man? Did she cheat on him with his brother???? 

i think she had a physical disability herself at the start they mentioned her limping but after that nope. so im not sure why but they never showed reasons why she was with him. and no she didn't cheat there wasn't any scenes showing it.