Being complacent

My friend’s fiancé is a shit human being quite honestly. He has terribly ignorant, racist, and quite wrong opinions. Anywho my friend and I were on FaceTime and her fiancé was having a background conversation. He said there was an Indian couple at the park and his child went up to them and he got scared cause they started talking their native tongue in which he continued to mimic insensitivily. Which of course rubbed me the wrong way but I know him and he’s a bigot and I always wonder why my friend decided to procreate with this man. My wife overheard and flipped her shit, then continued to call me a “blind kk member” and I shouldn’t let him get away with that (me being a black person). I just wanted to have a conversation with my friend and it went downhill real quick due to ignorance from my friends fiancé. I took what my wife said to me about being a “blind kk member” with a grain of salt coming from a white person but also coming from someone who used to own a confederate flag. I don’t wanna hold the past against her at all but it’s ironic that she got mad at me and not him. How would you handle this situation?