Long distance relationship?

my two older sisters were both in long distance relationships for many years. the boys lived in England while we lived an America (so, a bit different from my situation) and i've always hated when people said that long distance relationships never work because they ended up marrying those two people :]

i'm 16 and i've gone into one myself about 8 months ago. he's visited me twice within those 8 months and we had a blast each time, i felt like everything was perfect and like i was at home everywhere we went. but unfortunately, we haven't seen each other in a while, and i went through a phase of missing him to the point of incredible pain. i was also feeling very lonely as i do not have very many friends. i've recently noticed myself looking at other guys and considering whether they'd be a good partner or not, whether they think i'm pretty, etc. and it's making me uncomfortable. i feel trapped in this relationship all of a sudden, when not 3 months ago i was absolutely crazy about my current boyfriend. and he's so close to moving here! i hear this happens sometimes in long distance relationships but...is it just that or does it sound like something else? should i break up with him?