I’ve NEVER heard the science of that in my life, so I went to look into it because everyone has been saying that (I know it’s a widespread thing, like Chinese novels are full of that misconception) but I still could only find OKs in online health sites and still didn’t. Maybe I’d need your sources for clarification tbh because that’s not what I’ve been taught!
e.g.:
https://www.healthlinkbc.ca/health-topics/hw194974
https://www.healthline.com/health/pregnancy/sex-first-12-weeks-of-pregnancy
https://www.mayoclinic.org/healthy-lifestyle/pregnancy-week-by-week/in-depth/sex-during-pregnancy/art-20045318
Isnt he pregnant? That would 100% give him a miscarriage