Its name is literally "what? crown prince is pregnant". You can find it on mangatoons. You can slowly get it for free with reward gems you get just for logging in daily
a new rival from my experiencw with this genre, i'd say she's a childhoodfriend or calls herself his fiancé bc she's had a crush on him or their parents are friends or something along those lines just my thoughts tho, i didn't read any raws or something
Oof