FA ex is orbiting me when in a rebound

I've always heard that some early signs that an FA is thinking about you or thinking about reaching out is if they start orbiting you / stalking you on social media.

For the past week, my ex has been stalking me and logging onto one of our fav games everytime I am active, but he rebounded and has been with his new gf for 6 months now? Why is he orbiting when he has a new gf??