How do I act at Divorce Mediation to get the best result?

I have been married a little over 3 years and my husband and I have separated 2x. I filed for divorce last year and he talked me into coming back. We have been to counseling 3x and I have done everything I could to make it work. We are separated and going thru a divorce…he wants all my assets (mine are substantial and his are nil). I want to keep whats mine and protect my son (from previous marriage).He threatened to punch him in the face to "discipline" him. I had enough of his lazy a** and threats. When he moved out the last time, I filed and won’t let him come back. I want to protect my son from all this. I want to keep my assets. What do I say or not say to the mediator?
I have a lawyer. the judge we are going before, requires mediation before he will hear a case.

professionally… make sure it looks like you need what you have to even get along in this world. and dont be pressured into signing anything without a lawyer. also make sure any threats have been logged.