Why dont i hear from my boyfriend when we are apart?

me and my boyfriend have been going out for 3months, its long distance and he comes over to see me every time. even though i have offered to go to see him. when we first met we text all the time and spoke on the phone, now im lucky if i get one text per day...he never replys to my text back. when we do see each other its really great and we talk about things in the future, then he leaves and i dont here from him much! its driving me mad becase i dont want to seem needy, demanding he call me every day, but a bit of banter and phone calls would keep or relationship alive in between seeing each other! can any one offer any advice i really dont know what to do!?