Yes, he is starting to worry now. He thought he was holding the power by walking out then realised you had power to make decisions for yourself.
So now we have the ‘I have rights...this is my house too...I pay the bills’ because he is aware you will also be making decisions.
My ex absolutely shit a brick when he told me he wanted us to separate and I took him at his word and found myself somewhere else to live.
They want to call the shots, be in control and really don’t like it when you start to take control of arrangements yourself.
You know his game. Every time he sees you on your phone he will be worried. Every time you go out he will wonder where you are going. Every time you take a call he will feel even more out of control.
He’s brought this entirely on himself.
However weak you might be feeling at the moment OP, he is weaker.
However difficult it is for you right now, play relaxing music, seem happy and relaxed in front of him, pretend none of this is impacting on you, do nice things with your DC, do nice things for yourself.
He wants you to rant, rave and cry. Do exactly the opposite.