its natural to think stuff like that but its also really important to catch yourself and tell yourself it's just a fairytale, otherwise you won't move on.
It's not unusual to do that. I would definitely kick that habit quickly though. From personal experience constantly thinking or looking in on your ex can be a slippery slope into sadness/depression.
Yeah, I would agree with everyone here. Had the same thing, but later on I realized it was a bad habit so I just keep myself busy and worry about my life instead