"I think he is afraid of his son being different, and that is all it boils down to."
Well, the fact is that he is going to be different from *someone*, no matter what choice you make. Disclaimer -- to me, the social argument is not valid (not even if 100% of men in our society were circumcised!,) but going on the assumption -- that is, working from your husband's mindset -- that it is, here is what I would say:
Non-religious circumcision is something that happened for a very small part of human history -- several decades of the 20th century -- due to the notion that the foreskin invites disease (wrong) and that it aids sexual pleasure (right) which for a time was a big no-no. For no other reason were millions of men deprived of a functional organ. As the public and medical establishment have slowly become educated, the circumcision rate has dropped. In 1950 nearly 100% of male babies in the United States were circumcised; the rate has fallen steadily to where it is nationwide under 60%. In some areas the circumcision rate is closer to 40% (as is the case where I live.) Assuming that these numbers will continue to drop -- and they will, bar society becoming severaly sexually repressed again, because the science is on the side of keeping the foreskin intact -- by the time your son is an adult, he will be in the minority if he's circumcised.
Your husband is no doubt concerned about the present though. In other words, will your son be ostracized and humiliated when he is eight years old in the school locker room? If your husband is right -- if boys and men in your community have occasion to size up each other's penises and are obsessed enough with the way penises look to actually make judgements about them -- then it's a valid concern. Maybe that would do more harm to his psyche than not being sexually complete. But from my perspective it would be better to remove my son from such a repressive, judgemental culture than to permanently alter his body, without his consent, to fit into it.
My first husband was from the deep south, and I spent some time there with him. Despite initially believing that I was strong enough in myself to not be affected, my self-esteem plummeted when I was constantly being bombarded with messages that my natural self -- hairy armpits, plain hairstyle, no makeup, small breasts, big thighs -- were not acceptable in that culture. Rather than compromise that in myself which made me true and whole, I chose to leave that culture.
This is kind of how I think of body modification in general. If it is bogus for me to have to get breast implants or have liposuction to be acceptable (or, in other societies, bound feet, or female genital mutilation, or what have you) why isn't it bogus to remove my son's foreskin? In the cultures and sub-cultures that promote such body modification -- often without the consent of the person it's being done to -- they regard the modification as either an improvement or not a big deal. Looking at it from the outside, though, we have perspective to see what is being lost.
And what if -- just what if -- your son doesn't experience the locker room judgementalism that your husband apparently has? What if he goes off to college or to live somewhere that the circ rate is negligible, and he learns what foreskins are for? How will he feel when your son asks him why he removed a sexually valuable part of his anatomy?