I'm thinking about sleeping with my ex husband
Are you serious? Why do you want to sleep with your ex husband?
He's so nice to me and we never fight
There is nothing wrong with wanting to sleep with your ex husband. As long as you both consent and you are both single, it is fine.
But he always was a jerk in bed, always wanting to do the same things.
It sounds like you aren't so sure about your ex. Maybe you should really take some time to consider the pros and cons before getting involved with your ex.