@goodhunter I'm binging the series at the moment, so I dunno if it's pointed out in a later chapter or what, but since the MC's literally irreplaceable to the village's livelihood, he's basically not allowed to leave, so he can't do it himself; and, as you pointed out, since all the girls are head over heels for him (I mean, he's basically a nigh-invincible demi-god who can (potentially) one-shot an elder dragon, so the mere chance of those abilities being passed on to his offspring would get primal breeding instincts firing on all cylinders), they're not going to be in any rush to do it, either.
As for the girls' and their rotation, I counted some chapters back and at that point, he was sleeping with 71 different women; I don't remember off-hand, but I think only Hakuren has joined that number since then. If it was one different woman every night, he'd only sleep with the same woman once every two and a half months. As a point of reference, with this system, if he slept with Tia on January 1st, the next time they slept together would be March 14th, so I don't see how it could be anything other than several women taking turns over the course of the night.
This was also alluded to once or twice where he mentions "not really sleeping" at night despite going to bed at about the same time as the rest of the village; and while he's only really "tireless" while using the AFT, his stamina was implied pretty early on by the fact that Ru begged Tia for help and then they casually tossed him to the other elves because he was implied to basically be wearing them out.
