How should I bring up divorce to my spouse of 3 years while I'm deployed?

I am currently deployed to Iraq and I have come to realize that I am unhappy with my marriage. My husband is also military but stateside. We are both very young and got married too early. I want to divorce based on irreconcilable differences. I do not know how to tell my husband, he always says things such as "I can't do anything without you", "You are my everything" and "I miss you so much". I don't want to break his heart but I don't want to lead him on for 5 more months. I know it is a crappy thing to do while I'm away but I have been feeling this way about our marriage way before I left. I don't want to hurt him, but I don't want to lie to him. Either way I'm a terrible person and I think it best to just break the news to him now so he can have a chance to adjust to a single life while I'm away. How should I bring it up?