Why did my ex move on so quickly?

and so on.

I know from my own “misadventures” in love, that my ex’s were able to move on quickly because they were more attractive than I am, and far less shy, and sometimes because they were far less picky than I am.

Such as, if your ex moved on fast because they never actually loved you;

If you could instantly cancel one social norm, what would it be?

What I suspect you really want to know, is one or more specific questions.

or if they moved on quickly because they were secretly starting up with their current person before you broke up;

or if they moved on fast because they can control their emotions like a simple light bulb;

Is it better for 2nd generation Western Muslims to marry someone from their parents' country or a western Muslim who was born and raised in the West?

Different tack: I don’t think you asked what you want to know, you asked what you’ve heard other people ask.

Of the ones I was able to talk to about it all rationally later, some of them admitted they “used” a new “hook up” the same way some people use drugs, to dull the upset over our breakup; some said (perhaps as revenge) that I was easy to replace; some said they just got lucky. Most didn’t stay with the quick replacement, but a few even “panic married” the replacement, as part of being upset about the breakup.