You say she was insecure and that you broke it off with her.
If she really was insecure, and you really did end things, then is it all that shocking that she needs someone to validate her so quickly?
Insecure people can't be alone, they have to have someone 'wanting' them and showing them that they matter.
What I don't get is that you left her, and then wonder about what she does and try to figure out how she is feeling, why she moved on, etc.
First off, who the hell knows if she moved on. Who knows if she is a whore or if she had things lined up already, none of that matters. You broke up
with her and shouldn't be talking to her, thinking about her, or any of that nonsense.
If you are concerned with such things, you clearly have feelings for her and shouldn't have broken it off.
Move on with your life, and hope that she moved on too. I don't get why people want to leave someone and still have them be hung up on them.
That itself suggests insecurity on your part. If you care about her or used to care about her, you wouldn't want her to be all butt hurt over you,
just like you wouldn't want to be all depressed if she had left you.