ex keeps coming back

so I was with this guy for 2 years I was too young to have a boyfriend but I had one anyway we started to argue a lot like every other day and that is when I started doing things drug related like smoking weed shurms and I liked pills it was fun and all it took what pain I had and made me forget for a little and I started drinking with that too he started doing the same so when we was together I would pop some pills ECT i got cheated on after 2 years we broke up we both stopped the drugs we both would every once in a while smoke weed and take a pill or something then after a few months we get back together on and off for 3 months he cheated again so I say I'm done he is 18 now and I'm 15 but the other day he texts me telling me he has grown up and he wants to try to make things work so stupid little me decides to say yes we talk for two days then he stops texting me for three days I text him and asked what was up and he said that he went and hung out and got fucked up with the girl he cheated on me with so now he is blocked on all my stuff he can't contact me or any thing I'm still a lil hurt but I will get through it