how long a long distance relationship last can depend on many factors
1)has it been long distance from the start-
studies have shown that people who start with long distance can stay in long distance relationship longer(like people who meet on nternet) as compared to people who fall in love while they were close by and eventually had to go long distances due to other reasons.- this could be because you moving away could actually mean that priority is not eachother.
2)the loyality aspect
3)how effed up you are,people who r clingy and who has less self confidence and low self esteem tend to linger in the relationship as compared to people who have boosted self confidence .
4)how much effort you put onto spending time with eachother.
all in all the fate of long distance relationship cannot be generalised.