OK thank you for clarifying. I really am on your side. I was in that kind of marriage and know how you can become paralyzed with fear, not knowing what to do.
In the future, follow the custody agreement to the letter so you will not be found in contempt. If the agreement is not working, file for modification.
Your kids are 3 and 4 not infants. If they say things that are concerning, ask more questions. They can communicate. If they report things that are clearly abusive, then report to family services.