Men, why do you keep tabs on your previous partners if you have happily moved on?

I don’t mean just randomly looking up someone you haven’t thought about in a year or more but why do some men regularly look up an old lover on social media especially if it’s someone you were never serious about and you’re now in a much happier relationship with the girl of your dreams?

If you chose to block this woman and not stay friends why do you care to keep checking what she’s up to? Why block in the first place if you’re just going to keep looking?