Boyfriend is pissing me off

My boyfriend is pissing me off completely. We are currently pregnant and I used to be friends with a couple of girls I am no longer friends with due to events that have happened in the past. Well these girls on Instagram have requested to follow me multiple times after me denying them time after time. The only reason they are wanting to follow me is to be nosey because it says I am now pregnant. Even my boyfriend tells me not to accept them because all they want to do is be nosey. Well now, my boyfriend let one of the girls best friends follow him. I told him to block her&unblock her that way she doesn't follow him. The only reason she followed him was to be nosey. He won't do it either! He is cussing me out and acting like this girl is his SO and he can't let go! It's making me so angry. He won't just do one simple thing he's acting like he has feelings for this girl. What should I do?