You’re talking a lot about what [i]he[/i] wants. The trick for you is to figure out what [b]YOU[/b] want. Since he seems to be confusing you, you have a harder job in assessing the situation and deciding how to act, yourself.
Since you’ve only been dating six months, I’m not sure how many of those six months he’s been away. That would be good to know. You also didn’t make clear the nature of the contact between your boyfriend and his ex-girlfriend so I don’t know if he slept with her or just chatted with her on the internet, and how long that contact went on.
While there seems to be a lot unanswered, I think it would be wise for you to continue to play the field and consider other men as potential boyfriends. Actions always speak louder than words, and I think you have to weight his actions more heavily than you do his words.