Someone explain why they black hair ML had to betray the FL in the past?

I think he did that so she could become empress or something

He didn't betray her, he ordered her to kill him

Couldn't he have simply marry her and make her his empress because hes the emperor

I don't even know anymore XD

Sadly I think he got rejected or he thinks his love is one sided?

i think the emperor knows that stupid old noble fools are talking behind martina's success. they are afraid of her influence to the masses since she is not of noble blood but only a noble in title but people respects her and views her as someone whose authority is like that of an emperor. old farts are gonna target her life and he doesn't want that, so he wanted to give her the throne but she doesn't want that kind of power so he "plotted" her downfall so that she'll fight him and claim the throne... that's what i understood from it ╮(￣▽￣")╭

I think it was because of the curse.