Will my boyfriend forget about me while he's in the navy?

My boyfriend of 2 years is leaving for the navy in a couple of months. We are very close and have dealt well with long distance all throughout our relationship. I live an hour and a half away so we see each other for a couple of days every week sometimes every other week. We talk about the future and he always tells me he's going to take care of me and buy me a house when he gets out of the navy and how he's really excited to go. He has always been faithful and a good boyfriend. Very sweet and thoughtful. I don't know why I am scared that while he is gone he is just going to forget about me... I feel like he is going to enjoy being in it so much he isn't going to love me as much or that he is going to change while in the navy and when he gets out isn't going to want to be with me anymore. Any words of advice from people who have felt like this before? I love him so much, we've been through so much together, and I trust him I just hear how people change while in the military... I don't know what that change will mean for us?