I really want to know how to actually keep the child when she gets pregnant
You know, in the game corrupt kingdom(adult themed) there is children present. except, they're a separate mechanic(only non-pornographic part) in the game. You do get to keep them and they don't go to an orphanage where they can't be contacted. They do go to an orphanage that the MC owns but is watched over by another npc instead of the MC and can be visited. In a few text based games, the MC is able to impregnate(if male) or get impregnated(if female). the child goes away for an "X" amount of time and comes back as either an teen or an adult which joins the harem for interactions.
just penny for your thoughts, there's ways to work around it. Since, others have already done so.