my real mind to our relationship

This few days i m having a confused mind.. i really dunno the way to remain this relationship.. there are already 5 years we r coupled.. it is really a long time.. but i found that when he started his form 6's life.. the distance between us is larger n larger.. maybe the things he learnt n friends he knowed are different with me.. so the gap is started.. i m going to furter my study few days more.. so i really worried our relationship wil stop here.. there r really lots of sweet memories in tis 5 years.. i stil kept the seashells that we picked together at penang's beach..i stil kept the small cute toys that you made for me.. i stil remember every day everyday before i went to bed u wil told me that :" good night n love u forever n ever my lao po." but now, all are different. i really... dunno wad to do?? =_=