Think of it like this. If she had amassed this debt with a gambling addiction or a drug addiction or an alcohol addiction, would that be a dealbreaker for you? If so, then yeah, sure, time to get out. But if not, then just keep in mind that this is the same thing as all of those. Addiction is a disease and it makes people do illogical and harmful things to people they love. It can be treated and it can be solved.
It's not necessarily your responsibility to go through all that effort. You have the right to withdraw of course. But if you want to, and if she's willing to put in the effort, then it doesn't have to be the end.
That last part's important though. Nobody unwillingly loses an addiction. You can't take it from her. It's something she has to recognize the harm in and want, just as much as you, to solve.