Boyfriend and i are on the verge of breaking up, please help?

my boyfriend and i have had a lot of problems in the past and we have been on and off dating for over a year now. when we break up its usually just for a couple of weeks at most because we miss each other too much. we are both in college and go to the same school and see each other often. we are about to have another break up, but this time its serious. like if we break up this time it is for good and im so afraid of that because i love him and he loves me. the problem is that for some reason i just cant seem to be comfortable around him, i dont know if its jitters or something because i like him alot but i feel like i should be past that stage, we have been together for a long time. im very shy but when i get to know people i open up and can be myself. but around himn i am still stuck in the stage of being shy and not able to completely be myself. we have fun together but lately it has been bothering him bc he knows i am more outgoing around my friends, but not around him. we decided that maybe we're not right for each other and now we are contemplating breaking up for good. i just cant stand the thought of not being with him especially bc its my fault that i cant open up and be more outgoing around him. i really do love him i just get shy around him. i need advice, anything, i dont want our relationship to end. i know youre going to tell me to just be myself but its obviusly not that easy, im not a different person around him, just more shy. someone help, and fast, i want this to work.