Stop focusing on him and what he's doing. His moving around is not a form of emotional or mental abuse...it's just moving. They do this. Why? Because they want change, rent is too high, location is not good or just to be closer to the children or they move further away to be w/the op. Change is what they are seeking and right now, he's not thinking about you.
Mia, you have to understand that is this journey he's on is all about HIM, not YOU. He needs to grow up and in order to do so, he's got to face some issues, resolve them, etc., before that can take place. He's got to do this and you weren't part of his past life, so you can't participate in helping him through that period of his life. You have to be the strong parent right now and be there for your children. I know you are angry w/him, but the anger isn't going to help him. Take the anger and use it to move forward. Take that anger and apply it to some task that you absolutely hate to do and use it.
I don't want to see you get stuck and continue to churn your wheels in the muck. Look around your area and see if there are some free activities that you and your children can do. It's a way of meeting people and who knows, you just might make some new friends that you and the children came spend time with.
Keep the focus on you! Don't allow his move to ruin your weekend...it's just a move.
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.