Boyfriend scared of being too attached

hello, i need some advise my boyfriend used to overload me with attention and then he suddenly started messaging/calling alot less and once we were talking and he said he was scared of being too attached and he was worried he'd take a job in the US after over a year from now and leave me, i am now on a two week vacation abroad and feel need like he doesnt call/text me enough (we still talk everyday its just that he used to call/text all the time n i got used to it and feel something is missing