Most Helpful Girl
To prove to you that she found better and to make you jealous. To be honest, that is an insult. And I suggest that you move on from her. She just disrespected you. Block her number and delete it, delete anything on social media concerning her or the relationship and move on.
Most Helpful Guy
May be there is no reason as such, just wants to introduce her new boyfriend or she has an intention to try to make you jealous on purpose.