Kazuya, you sweet summer child. The Japanese red-light district industry has so many surprises in store for you. But he's actually acting like a prepubescent child who was told that all sex is immoral, wrong and evil. If losing his virginity means he was going to die as a condition, then I'd understand but isn't he overreacting to this? He's not asexual, is he?
I'm starting to feel bad for his future wife. She'll have to deal with a dead bedroom problem that might last years. Maybe he's the stick-in-the-mud kind of herbivorous guy who strictly believes that sex is only for procreation and once they have a kid it's over.
It's crazy how he immediately jumps to prostitution-adjacent services instead of asking one of the many WILLING girls around him to help test any theories. He'd rather pay a random girl than test his luck with either Haruka or Saki who are both ready and willing to kiss him (and more), and I'm sure Akari would be down for a repeat performance.
I think Oppai Pub could be translated as Titty Bar but it's fine either way. Thanks for translating!