I'm confused about feelings for my boyfriend.

We have been together for a year and almost a half. I feel like I do not have as much feeling for him. My mom has noticed this, I feel so-so, I don't really care to see him. I feel like we are getting out of the honey moon stage. It feels weird, I don't know what I should do. I don't want to break up with him, I love him. He is leaving for Basic Training in August. I don't know if its me trying to pull away from him, because I don't want to be upset about him leaving. I can't put my finger on how I feel. Nothing is bad about the relationship with us. I've talked to him, and he feels fine about it. Please give me some kind of advice.