Forwarded answer from Abu Rayhanah AbdulHakeem Al-Amreeki hafidahullah

Wa alaikum salaam wa rahmatullahi wa barakatuh Thank Allāh who removed you from this marraige. Hide her faults, for verily she is the mother of your child. Just imagine if she was innocent of what you are accusing her of, yet you were prevented from seeing your child, you would have to be patient. Therefore, don't let her shortcomings push you to exposing her sins. Do you want to see your child or do you want her to feel the pain and anguish you felt? Look at the whole picture. You will have to deal with this woman until your child is an adult. Don't make things difficult, your child will be the first to suffer. May Allāh aid you in this ordeal and reward you for your patience.