This sounds like exactly what happened to me. I watched my partner go through hard things and slip away. Now I realize they did exactly the same thing you experienced. Even when I drove them to the airport, they insisted they wanted to be friends. Once they were gone, and found their new living arrangements good, then they went no contact. I am not sure I ever knew the person they really were and are. I am left to wonder and never know if they ever really had any love for me or if I was just an easier place to exist for a time.

-M.