look, I really dit not want to be as blunt as I was, but he did only provided partial info so I only made the recommendation to cut the ties....
having seen his response about them being serious and about marriage, then I would be even more cautious.
the op said she did say she wanted him to go. the question is once again, did she make the decision to go, and then asked him to join her or did the both of them sit down together and decided she should go. because if she already made the decision and then asked him, then my assessment stands. she is looking to bring some familiarity with her to a foreign city. once her job settles and she becomes more comfortable with the new city, she will drop the guy, it's only a matter of time. women do this all the time, the majority of them are very wishy washy and the only way them to move to a new city is to bring the old bf, with all intentions of dropping him once she knows her way around.
now, if once she learns of the job offer, the first thing she did was sit down with him to try to map out a solution for both of them to be together, then yes, she is serious about him and wants him to be with her.
so the OP has to ask himself and look back carefully to see if she asked him to go with her before or after she decided to take the job. If before, go with her. If after, it is very obvious what her intentions are and he should cut it off before he gets his heart broken in a land he does not know or understand with no support from family. this is also a conversation the OP should have with the SO and not ask the board...just be up front and ask now before it becomes to difficult to ask.....
always be up front with each other.