You're very keyed in on every little thing she does/doesn't do. My parents call it being in an "obsessive-compulsive loop". It doesn't help you. What it says to me is you're looking for any little sign that you can pin your secret hopes on. Again, not helping you. I only think that because I've done the exact same thing. It only insures more continued suffering than is necessary because we do it to ourselves.
Xmas is family time. They did the tree thing with their mom and grandparents. You can choose to be glad the kids have extended family to support and love them through these times they have no control over.