Would I be wrong to tell the courts? I just don't want my kids to suffer.
The question really is, what's the chance of them suffering while he's using this stuff and you didn't take the necessary action to protect them. I know very little about the junk, but know it's illegal.
You chose to divorce him and it's your responsibility to protect yourself and your kiddies. If busting him for steroids means a safer environment for them, it's like your divorce...you've got to do it.
Blessings