I am not sure why people are surprised by this. the foreshadowing was set back in chapter 1 in the last two pages where she talks about raising someone into the type of mate you want.
Woah! I thought psycho play has stopped translating this manga but here we go they're back and we don't know how long they gonna continue doing this maybe they'll again lose interest in this manga and leave us hanging again for months....
He was pretty much abandoned by his father, by throwing him out. Btw Kaurako having feelings for Terumi was hinted way back and several times, like when he moved out to live with his girlfriend (not the yandere teach, the gym girl).