Probably because having one baby almost killed him... And some couples one want one kid so maybe it was just personal choice?
I think it's since he 1) he didn't go into heat after he had the first one anymore cause I think he got pregnant when he got his ear and tail 2) I think he turned into a vampire when the baby was like 1 or 2 so after then I don't think he had the Constitution of a female lycan anymore
I've read it again and saw that vampires aren't capable of reproduction, despite having a progenitress, whereas lycans could do it easily. Vampires aren't capable of reproducing life because they're beings associated with death. Being able to bear a child is only possible because Hwagok was still a female lycan, tho it almost killed him. But after transforming into a vampire, reproduction is impossible.
Why didn't Hwagok became pregnant again after 23 bloody years? I wanna see more beautiful babies from them ;(
Is it bc he wasn't a female lycan anymore??