How to apologize to my boyfriend?

im 17 and i had this friend who was 24 and he really liked me and always wanted to hang out with me but my boyfriend did not like me being around him or talking to him because of his age and because of the fact that he really likes me. So i stopped talking to him and seeing him like my bf told me too. Because i would want him to do the same for me. But last night i was laying in a blanket with my bf and idk i was getting too clingy so i was all over him and he was like what do you want? (after i kept staring at him) and i got up and texted the guy he told me not to talk too and when he texted back my bf picked up my phone and saw and got really mad. And didnt want to talk to me and i said im sorry but now he doesnt trust me. What should i do? How should i apologize? what should i say? How can i make him trust me again? I dont want little stupid things like this tear us apart (cause to him im always doing stupid things)