He crossed the line

My bf just got off work. We were talking on the phone. He said he was tired but wanted to talk. He knew I talked to my sister earlier today so he asked me how she was. I told him that she told me my nephew who is 9 is being bullied in school pretty much daily. He started working out last week because he said he thinks if he gets bigger then it won't hurt as much when he gets hit or slapped. I told my boyfriend this and that I felt really sad about it.

My bf didn't say anything in return. I asked if he heard me he eventually said yeah but everyone has problems and he doesn't want to talk about my nephew right now. In response I told him we were also talking about me because it made me sad. He got mad and said I was being childish and selfish and hung up.

I called him back and he hung up several times. I told him the only reason I was talking about my nephew is because he asked about the call with my sister. He started cussing and said he doesn't want to hear about that when he just gets off work and he's tired. Then he said "fuck [my nephews name]" .

I was shocked and hurt. And hung up. My nephew is 9. To me that's so low and crossed a line. I'm fighting the urge to calm him back because I don't want to be in a fight but I want him to know that is wrong.