My (23f) boyfriend (25m) made a very racist joke to his friend (24m) while we were at Target. Is this a massive red flat, a deal breaker or both?

So this afternoon my boyfriend, his friend and myself were at Target to get Xmas decorations.

There was a mom who was having a really hard time keeping control of her three kids and to me it just looked like a mom with 2 toddlers and a 5 year old. No big deal, but just for the sake of being accurate, the mom was white and kids were mixed race African American.

After they passed us my boyfriends friend looked at him and said "mixed race kids are always the cutest" to which my boyfriend said back "yeah, but I hope she enjoys being a single mother!"

I was disgusted. I truly don't see race and have so many African American friends and would never, ever, ever in my wildest dreams think or say something like that. I told my boyfriend that he needed to seriously think if he means such things when he says them. He told me that that he was sorry but I could just feel him snickering with his friend for the rest of the trip. When we got home, I basically went in to my room to read because i'm just so grossed out.

What should I do? Is this breakup worthy?

tl;dr: boyfriend made a very racist joke and I'm so grossed out.

edit: downvotes, are you f-ing kidding me?