Definetly do nothing without legal advice.
Is the car paid for?if not who does the payments?
do you have a car?
Do me a favor and take care of you and spend a little money now on a lawyer and safe yourself money on the long run. You can do all this without him knowing you doing all this. You are not saying you dont want the marriage no more you are just taking care of you and making sure tyou do whats best for you. Who is paying the mortgage right now? Those are all questions the lawyer will ask. You can get a temporary divorce agreement saying who pays what and snce he is the one moved out you have the upper hand.