He moved his girlfriend into our house and expects me to be fine with it.

He kept the house after we split, and i kept our daughter most weeks, and that was our deal. 2 months ago his girlfriend moved in. Now when I drop our daughter off on Fridays, there's a stranger's shoes at the door and her toothbrush in "my" old bathroom. He says I need to grow up and co-parent like an adult. Maybe I do. It still felt like walking into a house that used to be mine and finding out it never really was.