matilda - glad you've had a good day and recharged your batteries. 4 year olds are hard work - in a different way from teens.
bananas - I'm not sure that's always the case though. I think broadly speaking you do get out of a relationship what you put in. And if you attend parents evenings and drive them around, you will be part of their lives and know what's going on for them in a way that no number of treat concert trips will compensate for. Though you maybe should remind your DP to take the opportunity to do the odd treat thing with the DC from time to time, and not let that be only their DM's role. I've always done treat one to one things with my own two, based on things they like doing and have encouraged DH to likewise with his. But I guess cause of having 4 of them makes it harder - he always feels if he does fun stuff with one of them, then he's neglecting the other 3. Whereas because mine go to my ex's EOW, there's some free time for me to have one to one time, whilst my ex has the other child, whereas we have the DSC every weekend. And tbh right now we're struggling to manage the things we need to do, so treat one to one times aren't really an option.
Like with you, I think the pattern with his ex is partly a continuation of how things were when they were together - except she now has a new DP whose retired and does the school runs for the youngest every day, as well as my DH to provide money, and most of the rest of the parenting....
I've never been brave enough to try and communicate directly though. She won't hold eye contact, so I've not pushed it. Either DH does a drop off, or his ex sends her DP to our house - he's much friendlier so I communicate with him a bit. On the plus side - her strange way of pretending I don't exist does seem to mean she doesn't slag me off to the kids, or at least not that I'm aware.