You may want to realize that when you set a boundary, you are sometimes going to get resistance, right? You won't get a warning of when and it likely won't be consistent.
Be patient and step back. I don't consider it a backslide. I consider it correct behavior to call him out on his "promise".
I also think you're too close to be detached. If not, you may not have had to have that boundary.
You did what you did (and I think would have with anyone that did same) and I think it's time to put it in the rear view mirror.
Peace, AJ
"Our lives begin to end the day we become silent about things that matter" MLK Put the glass down... "Yesterday I was clever so I wanted to change the world Today I am wise, so I am changing myself."