There are various options to consider before divorce, including marriage counseling. You will have to decide what the circumstances require.
To answer your question about what you can do to protect yourself- don't lose your temper, don't ever engage in a physical fight, don't do anything that will give her false claims any credibility. She can say whatever she wants, and the police may come, but absent evidence of violence or witnesses the complaint wouldn't go far... and if she is as crazy as you say it is likely the police would pick up on this right away.
I see that sort of complaint from time to time and the story just doesn't add up. The best thing you can do is keep calm and don't run off if she calls the police.... if you do then they will only have one side of the story with nobody to explain how kooky she is.
