LDR is never easy no matter what the configuration. but it sounds like- just sooounds like, only you know for sure; that you have placed her as the sole person to fufill you romantically. While she is embracing new love as it comes as well as what she has now.
It must be hard to not be with your love all the time, and to feel like opportunities are passing you by with her while youre away. but think about who YOU may be missing out on while you are focused on this problem? maybe what you need is a walk on the beach in the rain with a new love
stay open, stay positive, and look forward to when you see her next instead of focusing on the sadness when you're not.
i'll get to put my money where my mouth is soon, one of my husbands is deploying in february
good luck hun!!