A, I'm so very sorry to see you are walking down the same path many of us have.
I would document every little thing I did on the inside of that house. Take photos of the outside, you know the before and after (when he does his part). I wouldn't let this man off too lightly, as he wants his half of the place.
Now, I have some thoughts on this ow situation. I think he's using your d to relay to you what he's doing or supposedly doing. You'd think he would be over there lickety split to clean up the yard versus working on ow's car.
I would move forward and remove him from my health insurance as soon as you can. You owe this man nothing. He's certainly not done much in the way of assisting you or your children the last few months. A, you are going to be okay. Start planning ahead and remember...it's the three of you now.
Next year will be different for all of you. You will then have the full ability to step up and not allow him in your home unless you want him there. No more of this walking in whenever he pleases and one more thing....don't answer the phone every time he calls. Play time in the sand box is over. Pick up your bucket and shovel and head home. Leave him in there to play by himself.
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.