If you already know his number was 8, why was it coming up in conversation again? Gee, were you trying to cleverly trick him into using a damning word like "yet"?

I'm gonna do some math here: 6 condoms at Christmas and you still have "some" left, so in 5 months, you haven't had sex more than four times. For the past couple of weeks he hasn't even tried, which makes you suspicious, because he usually tries more. So, let's say he's tried every two weeks since Christmas (approximately 22 weeks) and has only succeeded four times. That's an 18% success rate.

Why the hell should he bother?