Sperm being able to still produce

Ok..so I was told that sperm can live in in a female 3-4 days or maybe up to7.what I am wondering is. While it is still in you just swimming around is it still able to produce or is the sperm just there swimming around and then just goes away after a few days?

Its still working sperm while its in there.
Say you had unprotected sex on the 4th but weren't fertile till the 6th... you could still be pregnant even though you didn't have sex on the 6th because the sperm is still inside you from the 4th.

It doesn't produce anything...it just stays in your system for a few days... Don't you want to be married before you have a baby?