I think whats truly going on here Namemyname is that the assumptions you're accusing us of, really are more assumptions you have of this guy you're trying to see.
This isn't a situation where you are casually dating a few people and he's casually dating a few people locally.... this is a situation where he's flown out to meet someone and he's going to be there for a good span of time.
You can assume that he's going there just to date, and assume they haven't slept together, and assume its not a relationship, and assume he is going to come back and hang out with you, and assume he isn't just interested in sex, but its all assumptions because you haven't been talking to him all that long, and you have no lasting rapport with him.
You don't know what he's said to this other girl, or what the nature of their relationship will end up being... and you can't even be certain he'd tell you the truth if something did happen between them but he decided to come back and mess around with you too.
People here are giving you advice to what they feel would be the best solution to hurt you in the least... you're fighting it every step of the way. In the end you'll do whatever you want. If you want us to tell you this dude is legit, and he's not going to hurt you with his time away with another woman, which could very well happen often and none of us would be the wiser, I guess we could all forget our instincts and just do that....... you'll do whatever you want to do regardless of what we say anyways.
good luck.