I am sorry to say that you are not allowed to directly speak with or write judges in court matters as it can create controversy in his judicial duty to hear only facts introduced in court. You can however, write a letter or give letter to your attorney if you have one and request he file it in the district clerk office. You also can attempt to take letter yourself to clerk office and request it be filed for a fee , not too expensive, and the document will be in the file that the judge does review. He cannot directly accept information concerning your case so he may remain unbiased. You understand that in most divorce or child custody cases their or always conflicting parties and emotional problems. It would be a waste of time to address the letter directly to the jude. I suggest you write a formal , informational letter backed by facts and without obvious emotions or most of all unproven accusations. You may list concerns you have in a civil manner and request that they be addressed in court. Their are also now available advocates thru many agencies for children, abuse situations , etc. That can speak to judge in court for you are children. If you are a father that are getting the short stick which is becoming more common now, you may also locate an advocate ( they work for free,) thru family advocacy program.