When someone asks for it and argues about it something is up.
And maybe she argues about it because he's acting weird about it? Let's say it came up in some conversation, he freaked out, scared her and that's why she demands it now?
Interestingly enough, you're not accusing your husband of being a gold digger ;)
I wonder how many of the guys accusing girls of being a gold digger would sign up my kind of prenup :
-if we just break up I go with nothing but if he cheats or tries to hide money/ assets I get everything.
I doubt there would be too many willing to do that...