This guy is deployed in iraq right now, an is married. He told me that he still has feelings for me an still wants to be with me, an he also said that he is not geographically married since his wife isn't around. I'm just wondering about the rules with this.

If he's married it doesn't matter what country he's in he's still married

This screams bad catch on so many levels. Trust me he's married. There's no such thing as not being married because he went on a long business trip.

He's lonely. He's trying to deceive you in helping him in his selfish desires. In the long run, another woman out there will be hurt and trust broken because her husband that she must trust to not cheat, cheats! You will feel terrible, don't do it! Imagine what you would feel like if that was you in the wife's shoes. If your gut says it's wrong, believe it.