I'm not attracted anymore

We have been chatting here and there and keeping in touch since he went to the military 2 years ago. I never thought of it as serious, just friendly. He has always been there for me and super supportive. There is nothing bad i could say about his character.

Over time I felt like he took it too far and would call himself my bf (even when i said no). He likes to text me every single hour and tries to call me more than 3 times a day. I expressed how I do not want to take this so seriously since he is so far away and that I don't like constant texting. I have grown so unattracted to him because of it. I feel like a jerk for not wanting him. Advice?