What should i do ? what should i tell my boyfreind ?

hi me and my befriend been together for about 2 months and a few weeks. well their is this girl at school and my boyfriend told me that he liked befor he knew me and he knows that i dont really like her and he told me that he will never talk or text her to hbeaususe he knows it hurts me. so i told him that i cant stop u from being friends with her but he told me that he doesnt want to lose me soo he stoped. But about 2 weeks ago we were chilling and i toke his phone beause i need to call my mom and i saww a meassage from her and i asked him " i thoughted u stoped talking to her hesaid ya but shes my freind" i got soooo mad beause i get soo jealous. i talking to him yesterday and i asked him do u trust me he said yes then he asked me do you trsut me i said noo beause if i never would have found that text he would have never told me he talks to her. he told me that he would never like her agian in that kind off way that he loves me but ijust get this gut feeling that he will leave me for her sooo pleas help me my freinds told me just let it go but i cant i always thinik about it i dont want to sound to pushy to soo what can i do plzzzzz help ???? sooo what can i do or tell him ??