May I add we also need more backstory for him I think one chapter of back story ain't enough.
She didn’t only listened to rumours. At the beginning of her pregnancy she sure was scared and had some worry because of the rumours but after she passes through this and devlopped some feeling for him. But what she is angry at is that the emperor manipulated every thing and while knowing she was pregnant he told her that he would kill any women that are pregnant with his child. You don’t always need to know someone to resent them if they did wrong to you.
When he said I'll kill any woman who claims to be pregnant with his child because one women faked about being with him at the night ml had sex with fl
So he meant woman who faked being him or claims to pregnant are fake because he knows the identity of the women he slept. Ofc he said it in a way anyone would misunderstand.
ML has serious mental problems that I don't blame him for, he also doesn't know how to communicate very well I don't see him as the bad guy here. On the other hand I see why FL is worried but she knows nothing about him and just willingly listened to rumours and never gave him a chance, granted most of the rumours were true but we don't know why he did what he did.