I have read that in Texas at the age of 12 they get to talk to the court and pick. I can try to send you the link. I have been talking to several people and unless you are unfit the judge will probably keep them where they have been. Here's some of what I read yesterday.
12 years of age or older, a child can sign an affidavit stating whom the child would prefer to live with. If requested by a party, the Court will interview a child 10 years of age or older. Neither the affidavit nor the information from the interview is binding on the court. It is some evidence, just like all the other evidence. However, the court realizes the problems in ordering a sixteen year old child to stay with a parent with whom he does not want to reside. If younger than 10, the child might have the opportunity to speak with the judge. There is no guarantee of this. Law Offices of Raggio & Raggio
I am also sending a pm.
Btw do you think your stbx is doing it just to get you to worry and back down off of some of your other demands?