Hubby's Orgasm

RM
So when my husband isn't very vocal during sex which often leaves me to wonder if he actually ejaculated or not. (This poses a problem because we WANT KIDS so I NEED the SPERM!!) When I ask if he has ejaculated he says "I don't know, I think so" or some variation of "I think so, it's pretty messy down there." How do you not know?! I'm confused. 🤔 Anyone else experience this?!
**EDIT**
I can generally tell based on the mess (or lack thereof) when we are finished, but still. Why can't he just say it?! What's to be embarrassed about?! I would just hate to cut him short if the job isn't finished. Just because I'm all set doesn't mean you are. Ya know?!