Tagging in. Here's a cut/past of my last post on previous thread for info purposes;
I agree with Cool. Theoretically he could do whatever he wanted, even if he stays. But by not paying (or helping to pay) the mortgage he would risk the flat being lost to foreclosure (and the resulting credit nightmare) if you aren't able to pay it yourself. Same for any other joint bills, he'd risk becoming a bad credit risk.
As far as the car, I know here (US) it's pretty hard to get rid of a car without losing money on the deal as they depreciate so badly. Most just end up selling for what they owe on it if they have to get rid because the payment is too high. But could you look into refinancing? My niece (again, US) just re-fi'd her car and cut the payment in half. Basically, for the same reason. She and her fiancé aren't getting along and she's making preparations for a potential change in her 'living arrangements'.
Maybe at this point it would be best to just assume the HH expenses are going to be handled as before, with him paying the lion's share. It would be better for you financially that way. Just be prepared for him to want to change things, especially if he sees it as a way to 'force' you to give up the flat to him.
You are sure that your name is on the mortgage and deeds, aren't you?