Once a complaint is made, the decision about whether to proceed to bring criminal charges is based on evidence (witness accusations included) that the prosecutor reviews.
Many times prosecutors see right through the accusations of the ex-spouse. I have seen the matter being discussed in terms of it being a "civil" not criminal matter.
Hire an attorney to protect rights.
Yes, it not only could happen it does happen all the time. Hence the need for criminal defense attorneys.
I'm sure you've heard the line in a million T.V. shows "anything you say can and will be used against you in a court of law." Police officers have a way of twisting any statements you make into an admission of guilt. Even if you know you have done nothing wrong you should NEVER talk to a law enformcement officer about the facts of a case without talking to a lawyer first. Be aware that they may attempt to bully and intimidate you into talking. Practice these words "I am invoking my right to an attorney and my right to remain silent." Say it politley, but firmly. Then use your right to remain silent, until you have consulted your attorney.
Whether to file charges on accusations of a minor nature are at the discretion of the police while more serious crimes are screened by the felony review unit of the State's Attorney's office. Wild accusations arrising from failed relationships with threats of fingerprints and sexual misconduct are the stuff of pulp lawyer shows and are seriously revieded by those with the power to charge and arrest before action is taken. That being said, any accusation and threat of filing charges should not be taken lightly. Such threats may be crimes in themselves.