boy trouble

so I've been talking to this guy for about 4 months and we've recently gotten official, he sent me a promise ring too. he hasn't been in a relationship in a long time (I haven't either) and hes used to being cheated on and left. he said I need to be patient with him as hes gatting use to being in a relationship which I am. the only problem is, i have my fears. I'm scared one day hes gonna wake up and not wanna be with me. I'm scared that I put a crap ton of effort into him only to get hurt again. were both military so I know finding the time is hard but when I know hes free. it's tough. well be fine one day and then the next hes short with me I'm so scared that I dont know why to do. no one to really talk to.