They keep mentioning pregnancy. I hope they actually have consequences for that and it's not just a background element thrown in for a fetish. How the hell is he going to raise all those kids? Are all the girls really okay with it, it seems like of them didn't know they'd get pregnant. I hope we actually see his kids born, and I also think it'd funny if he gets in trouble for knocking up the wrong girl or something. So far he's been reacting like, "I'm gonna be a father to 12+ kids? Cool, that's chill. Whatever."
Well, he had been careful until now with which girls to impregnate.
Majority of the girls he had fucked until now are prostitutes, so there is no situation of
"gets in trouble for knocking up the wrong girl" yet.
Also, as mentioned in one of the previous chapter, the upcoming Dungeon work that MC has taken apparently rewards him with enough money to help him financially support all the impregnated girls until now.
Plus, since majority of them are prostitutes, i don't think they are the type who would pester MC to help raise their kids, and instead might prefer to remain single mother's.
Heck, the Halfling girl from this chapter even says that she wants to get pregnant and return back to her homeland to live (she doesn't plan to stay with MC even after impregnation).
MC is chill because he has accepted the fact that if he wants to become stronger, he has no other choice than to impregnate women, else he would remain weak. Worrying about the unborn kids now when even the most earliest birth is still months away is not going to help him (I mean, plot timeline wise, I think it's only been about close to a month since his first successful impregnation, so that's still like 8 months away for the birth of his first child).
Plus the stronger MC gets, the more he can earn.
Aka., the more children MC has, the more powerful he becomes, and the more he earns (because he would be able to challenge more difficult dungeons).
Not to forget, different world might have different standards with women not asking their child's father to take responsibility for the upbringing of the child (can happen, if population of male is lower than women, though i don't think that's have been mentioned in the story).