The damage has already been done... You have one of two choices to make now...
1) Tell her absolutely not and the two of you lay down ground rules for the relationship that do *not* include things like this (that either would be upset if the other wanted to do it.)
2) Pack her things
NOW... Even if she doesn't live with you, she has left things there or given you small tokens... Give them to her ASAP and tell her Bye. Have fun. Don't ever come around or call me again IF you (she) comes back... Include that if 'your' relationship means so little to her that she'd hurt your feelings like this, then there must not *be* a relationship on a two way level.
Getting a 'temp' job traveling on a tourist visa??? Hmmmm
Guys don't know how hard it hits to come home (or to the guys house to visit) and see the little teddy bear, cards etc etc that they gave the guy in a box sitting on the coffee table.
It took me
5 years to make up for a very small transgression that wasn't nearly as serious as this one would be. If I told MY old man I was going off to stay with a (even a known) guys house, heads would roll. He'd not hear a second word on it. (And THAT would be even if the person I was staying with lived down the block, not halfway around the World lol)
But college age is a hard time to be true to one another. Most aren't even positive what sort of job they want let alone be serious as to whom they want to spend their lives with.