I know of a case where this very thing happened. The boy was a professional dirt bike rider and he fell off and broke his neck. His fiance rushed to his side as did his family. It turns out the term Paraplegic is merely the injury. It does NOT mean they will never walk again or ever feel again. Some don't. She offered to go through with the wedding but he wouldn't let her. They are still engaged and she is living with him in his parents basement. He can walk a few steps on his own now a year and a half later. He is getting pretty self sufficient. Unfortunately bowel response is the last thing to ever come back feeling wise so even though he can move around now, so he still has to wear a diaper. He hopes to be able to change it himself soon. He is still considered a paraplegic.
I believe in the same situation, I would just put off the wedding until I saw what would be involved for the long run.