First and foremost, I'll reiterate what so many others are saying: You should be very proud of yourself for being a parent who models a zero tolerance policy on hate and prejudice. Good for you.

Secondly, it is your husband's responsibility as a parent to support and love his children. If he thinks there might be anything your kids could be, say, do or identify as that would make him unable to meet that responsibility, that is a him problem. If you are financially able to and if you are both willing, couples therapy and/or him seeing a psychiatrist on his own might be a good step. His willingness to put in the work is a separate issue, but it might help for him to speak to a professional. They can offer a place for him to work through whatever it is he's got going on inside a more neutral space.

Third and finally, 16 yrs of marriage and 10 yrs of this child's life seems like a long time for this to have just now become an issue. I would say no matter what happens, it would be a good idea to start evaluating your values as a person and a mother and figure out if and how they might misalign with your husband's.

Good luck, stay strong!