As the previous answer suggests, this is far from straightforward and the one thing you MUST do is seek legal advice to protect your own best interests.
It's time to look after number one, and to forget any notion that you can rely on free advice, however well intentioned it may be. Or that this is something that can be informally agreed between you and your ex.
I'm not a lawyer touting for business, by the way - I just know from personal experience that if you cut corners now, you could be facing a disastrously expensive situation, financially and emotionally, months or years down the line.
I'm also a man, and he sounds like a typical male control freak to me - all this can be resolved provided you listen to him and go along with his terms and conditions. It's not up to him to call the shots, and you shouldn't be intimidated.