Kids and I were also talking about baby's upcoming 2nd birthday in March and what we wanted to do. I really want to not have the huge bday party and go to Disneyland. Kids want to go too. Something to start planning now.
I thnk you need to prepare yourself for X wanting in on your b-day plans for baby. This would be a good time to set a boundary. If you don't want him to join you then say so! Say "X we are not a family anymore. I am celebrating baby's b-day with MY family. You can celebrate with her during your scheduled time."
"You can't stop the waves, but you can learn to surf." Jon Kabat-Zinn
