Maybe sit down with her again and talk to her about it. Does she still have a chance to accept it? Did you explain to her that you need the money and that if she hates her job that this might be a great opprotunity?
There may be other underlying reasons why she didn't take the job and I think that you guys need to sit down and revisit the discussion, even if she doesn't take it. These are things you need to discuss so it doesn't come back in future arguments because you both didn't resolve the issue.
and just to play devils advocate here maybe she isn't taking the new job because she only has 3 years left at this one and it is stable? don't shot the messanger, I am not taking sides LOL
just trying to understand why she didn't take the job.