You are so right and it is good to 'see' this early on before I make the mistake of being in control!
My STBX actually wants to spend time with them and is quite upset when they don't want to. But he lets me ask him rather than being proactive. SO now I will see about setting up a regular schedule with him. Easier for the kids too to have a 'plan'.
It is a process. Because he lives in an apartment now the kids don't have their own room. Hopefully soon he will be able to get a house with space for each of them so they can have some of their stuff there. They complain there is nothing to do at his place right now. To be fair he is trying. As I say - it is a process - for all of us.
Thank you - you are all REALLY helping me to NOT make the mistakes.