Absence makes the heart fonder...

i always wondered how long-d relationships can be maintained without frequent meet ups and sms... is this just my immature thinking??? if it is... can someone please teach me how they do it???
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i feel that at the beginning stage... absence does make the heart fonder... however... as time goes... i don't know if the same theory still applies... there's this chinese saying 'shi2 jian1 ke2 yi3 dan4 hua4 yi1 qie4'... it literally means that time can lighten everything... and this includes wounds... hurt... and even love! so in a long-d relationship... what happens when the feeling gets lighter and lighter due to the amount of time both parties have been separated??? do they try to rekindle the love or do they break up??? how is it possible that one can survive in a relationship just thinking that 'i know he loves me and is thinking of me 24/7 as well... so just hang on!!!' i don't know if i have that kinda maturity man :(
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in fact i'm afraid that i DON'T HAVE that maturity level to think of a relationship that way... and i'm afraid that my long-d relationship will not last... sigh... can someone tell me what to do???!!! i need counselling... it's just freaking 2 days and i'm complaining so much... but i guess... as time passes... i'll complain less and less and eventually.........
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i also don't know what will happen :(