Seperate finances now. Tell him what his contribution is to the household finances since he still lives there and figure out your approximate child support amount. My H pays 20% of his income to me for CS for our son. Get your own checking account and or have him get his own.
If you are going to stand for your marriage, tell him you intend to stand for your marriage. Tell him that your commitment and devotion to him are unchanged but given the current situation, you are preparing for the future the best way you know how.
This is what worked for me. Take from it what will fit your sitch.
"No one can make you feel inferior without your consent." -Eleanor Roosevelt. M-42, H-42. M-22yrs, together 27yrs, Sep 5yrs. D-22, S-18 I'm a survivor