My ex moved on so fast. How can I overcome the pain?

On their side, there has been a process of emotionally and mentally checking out while you were still together and while you were under the impression that everything is cool.

Simply put, because they have been prepared and you weren't.

And during this process, they either started seeing someone new who they planned to secure as their rebound option or were busy creating their post-breakup plan.

Why are so many US conservatives in this day and age still against racial mixing? They won't say it in public, but they are still against the mixing between Blacks and whites? Why?

This is why comparing yourself to them in terms of the healing process isn't going to help you in any way, shape or form.

I.e. you thought that you had the perfect deal whereas they had already made up their mind and just weren't as emotionally invested in it as you were.

So, don't try to compete with them.

What’s the weirdest phone call you have ever received?

You both are on polar opposites of the scale.

Instead, focus on taking care of, solving and healing what you are experiencing right now.

What they do doesn't matter and it's completely irrelevant to your healing process, though it’s valid to hate and judge them harshly for leaving the way they did.

How long can someone with narcissistic tendencies maintain a facade of fake love before their true self is revealed? Is there a specific trigger or amount of time that causes them to reveal their true nature?

This happened long or shortly before they physically left.

This is why you can't expect them to feel anything close to what you're feeling right now, because you and them are on a completely different stage in the healing process.