I am not certain that you will have trouble proving anything to a judge about a drug addict who used drugs in your house where the child was living. If you feel she is going to be too lenient, ask her to amend the order in light of the circumstances, stating you were giving him the benefit of the doubt, assuming he was clean when you first petioned the court. That is reasonable and you are acting and reacting to the information as you receive it----and not just he said/she said. Therefore, now that you know, you want to amend your request---but I suspect she will have a few things of her own in mind.

Express yourself to the judge as you have done here----and I suspect you will prevail. Your child deserves to be safe and not be at risk around this behavior your ex seems intent upon perpetuating.

Let me know how it goes.