So....some great news!
After mulling over it all day, DP could tell that something was on my mind. So I told him how I feel about it, that it really is a deal breaker for me.
He said that to him circumcision is preferable, and he feels like his hands are tied with this, but if it is that big a deal for me then he would never pressure me to consider it. He is disappointed, especially that it would be breaking "family tradition", but will respect my feelings about it.
Seriously, it is SUCH a relief, I feel like a weight has been lifted from my shoulders. I was stressing so much that it would turn into a big argument, so I'm glad that it didn't.
Situation successfully diverted! Thanks to everyone for your input