My “friend” is threatening to tell everyone my boyfriend and I had sex

I am in high school and I have told my boyfriend many many times not to tell anyone how far we have gone. My boyfriend told his friend every detail about our sex life. That friend texted me naming that we had sex and I have given him head and he has eaten me out and so on... I do not trust this guy and he has threatened to tell people about everything. I have and and begged and yelled at him not to tell anyone but he just keeps saying he will do his best not to say anything but he’s not making any promises. This guy had a loud mouth and I know the girls at school are going to slut-shame me even though it is my business and my body. I don’t know what to do. And I’ve asked him so many times and my boyfriend just tells me to ignore him but am trying to be friends with him and play nice with him just so he won’t tell anyone because I hate him so much and I’m scared of what he would do.