how do i leave him?

what is the best way to leave a guy? I want to leave my bf charlie because we act more like friends around eachother and i like being friends, but when he wants to take it further i just dont want to and he dosent know why. i went out with him because i thought that we would be a good couple and we knew eachother for the whole year. He has depression so i am also afraid that if i leave him he might do somthing. like hurt himself or even worse, kill himself x.x
can anyone help me out?

but he will start to cry and run off and kill himself, or say i am lieing to him and that i just hate him then ill make him life even more imposible. he already thinks he is an awful boyfriend so if i leave him what willhappen to him will he be ok?

ok, thanks ill try that ^^ i hope i can actually go threw with it x.x i shouldent leave him by telling him on aim right? phone or school would be better? well maybe phone cuz school is less embarassing.