Legal Question in Family Law in Louisiana

Usually, the Courts will order that neither parent can have an overnight guest of that sort while the child is staying with them. There is no law against living together or having premarital relations, but the Court will order that your ex cannot do so while your child is in the home.

The first thing you should do is look at your Judgment. The same Judgment that awarded you joint custody likely addressed this issue. If it did, you need to file a motion for contempt, as your ex is in contempt of the Court's Judgment. If the Judgment does not spell it out, you need to file a motion to modify the custody arrangement to add that stipulation. The Court will very likely agree with you.

It should have been in your Joint Custody document. If not in it, you need to file to add that. If it is, then a Rule for Contempt is appropriate.