The actual assault is not usable, but if it causes you to behave in abnormal ways, then they can use that. You should not be fighting this without an attorney. A good family law attorney can help you defend yourself and your children.
You really didn't post enough here to allow anyone to fully evaluate your situation. I suggest you speak to your attorney about your concerns--if you have one. If you don't, get one. Secondly, I suggest you get into treatment for PTSD, if you do have it. No one would fault you for trying to get better.
I am not intending this to be legal advice, because I don't know the particulars of your situation. Call me if you would like to discuss this or other isues.
I agree with Attorney Moore. This is a really, really complicated circumstance and without all the knowledge of how your ex is attempting to use it, we can't really make a judgment. Tell your attorney if you have one and if you don't, I'd strongly recommend you get one. This ruling can go either way, depending on the circumstances.
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