it seems like you have trust issues,...like my girlfriend always says,..a relationship is built off trust,..if you have any doubts in your head that there is any chance she will ever cheat on you,..its best to leave the relationship,..because the insecurities will haunt you and eat you up inside,..if she has feelings for him and she told you "i dont know if i want to be wiht you when i get back" its best to break up with her before she says anything to you,..i think the less you know (which is the stuff she will tell you when she gets back) the better off you are