Kenny it's often the women in this forum who are left with their partner's debt because the men traditionally handle the money but, male or female, it can be disastrous. I second Lexie's suggestion that you seek legal advice to see where you stand, as you may be responsible for a debt you didn't incur, and knew nothing about. This is important if you're thinking of leaving, even in the medium term, because she might comfort herself with a spending binge.
Legal advice gives you the basis for a plan. You don't have to walk out the door tomorrow, in fact that might be the worst thing to do, but you can lay down a plan to protect yourself from unintended consequences.
It's possible your AW had always counted on you to be a back stop no matter how bad she gets. You fear that she won't be able to look after herself with you gone, but what incentive has she ever had to try? Just pointing out that it can go both ways with As, and having to rely on themselves can be the shock they need to recover.