Personally, I'd like to know why she's against it. The entire argument that it's cruel is kind of ignorant. As far as damaging goes, I'd highly doubt that there's any threat. People were doing it in 4000 B.C. and still reproducing. Also, the reasons for getting circumcised is both traditional, and practical. Practically speaking, one who is circumcised will not carry an STD as easily as someone who is not. This is also just a healthy practice, for both the man and his... wife, as the other member ought to be.
So like I said before, if anyone could explain why guys shouldn't be circumcised, I'd be interested in reading your thoughts.
I'd say more, but we're not all guys reading this.