Are there any activities that the kids and your h could do that wouldn't involve you being there? Once in a while, you might want to go separately if you have something else you can do on the way to or from the activity which wouldn't include the kids. Maybe you might want to do something for yourself sometime and he can be w/the kids on his own.
You don't necessarily have to be readily available to pick up the phone, text a response back to him or be around when he's there w/the children.
You have to determine how you want to handle this and it's not about making the change so that it will feel it. It's about you being comfortable w/whatever changes you make and they have to be permanent. It's about detachment and you can't detach very well w/him being under foot and he has to learn to deal w/the children on his own.
Sit quietly, the answers will reveal themselves when you least expect them to. The past is gone, the present is a gift and you need to focus on today, allow the future to reveal itself when it is ready.