People who go to school taking out student loans should generally be expected to pay them off by themselves, without relying on their spouses, even if they are not naturally confident. You can talk about lack of confidence only in a person who is trying her best. If she loses ten interviews in a row because she keeps fidgeting during the interviews and speaks in incoherent sentences due to severe anxiety attacks, well, then you can blame lack of confidence. So far it has been just pure laziness. You need to call a spade a spade.