BOYFRIEND ADVICE? Losing interest HELP?

[Arrogantclub390]

So, we've been together for 3 years now. The beginning of our relationship is so happy! Everything is perfect. I get butterflies in my stomach everytime he calls my name and everything that he does involving me. I won't forget every details he does for me. But now, my feeling for him changed. Not always, but sometimes I love him but sometimes, I lose interest in him. The spark in our relationship has vanished. I don't have any guy I liked or something. I just don't know what to feel for my boyfriend. I went on a vacation for 2 days. I sent him a goodmorning message (via Facebook) before I left the house because I don't have a phone for 3 weeks. He only replied once and after that he didn't sent me anything. But when I came back home, he chatted me and he said "How's your vacation? I missed you!" but I don't know what to feel. When he hugs or kiss me, I don't know what to feel anymore.. I don't want to leave him but I guess my feelings for him fades sometimes. I feel like I want a break or something but I don't have a valid reason to do that. I need him in my life. I don't want everything about us to be a memory for me but I don't know what I feel for him anymore. I have no interest in being single, or a different love interest interfering. I still care about him a lot. I feel horrible since I have no real reason to feel this way. Why have I suddenly lost interest? I honestly think that I'm starting to lose my interest in him. And it pains me. HELP? (((
PS: I love him, but for some reason my interest in him is decreasing. I feel like whenever I see him, I love him. but when I'm away and out of his sight I always feel like I don't have interest to talk to him or something. I let him do anything he wants (videogames etc). I don't want to complain these things in him because I feel like I'm a strict girlfriend and I don't like that and I feel like im forcing him to change. But I feel sad when I don't receive messages from him. What should I do?
PS: I love him, but for some reason my interest in him is decreasing. I feel like whenever I see him, I love him. but when I'm away and out of his sight I always feel like I don't have interest to talk to him or something. I let him do anything he wants (videogames etc). I don't want to complain these things in him because I feel like I'm a strict girlfriend and I don't like that and I feel like im forcing him to change. But I feel sad when I don't receive messages from him. What should I do?