My bf lets his ppl disrespect me

For the third time ive been disrespected by somebody in my bf family and i take it i showed my bf this message I received from his ex sister in law im guessing she upset about his brother now talking to my roommate so threatened to fight me,  my bf laughs shrugs his shoulders nd says nothing so im I responded myself i tried to be mature,would yu be upset if your bf reacted like this ik it sounds sexict but im use to being with a man who stands up for me of course i can handle it myself but he didnt seem mad that somebody was talking to me that way