In Mushoku Tensei the MC couldn’t get it up for a while. Though this does happen around volume 6 and 7.....hopefully the amount of volumes doesn’t scare you away since this is a great read as well
I Feel like 90% of Chinese authors should do that instead of doing the shit they call romance in their novels.
hmmm... maybe Paradise of Demonic Gods ? MCs emotions are sealed. He does claim he still has lust, but judging he hasn't done it with anyone in over 1000 chapters... (and MC isn't a virgin either). It's also possible since he only has 5 years to live, he simply avoided useless distractions too...
Tsuki ga Michibiku Isekai Douchuu. He keeps using the 'family' excuse, which is what his sister mentions in one of the extras.