Why don't long distance Relationship work?

hi ive been wit mi boyfriend 4 1 year n it has been great up until now because he have 2 move 2 a whole differnt state!! n i dont want 2 break up wit him but mi friendz say i should b4 i get mi heart broken.... because hez movin 2 d same state same neighborhood as his x girlriend n mi concern iz dat he will cheat on me wit her......he once did b4 because he got realli mad because i wouldnt have wit em n he w3nt n did it wit her win he went n visited his farther n im onli scared dis tyme if hes goin 2 stat der 4 good should i just call off d relationship now b4 i get hurt or should i stick it out mann im so confused wat should i do n yes im n l0ve wit dis dude.....