Co- parenting frustration?

VENT! Does anyone else have issues co parenting because of your ex's new gf/so? My ex husbands has completely ruined our communication and now he doesn't even communicate with me. It all comes from her and she is a bitch. Most difficult person to deal with on the planet! My attorney says to let her so we can show a judge how my ex can't  co parent when we go back to court.