Please Answer-What The Hell ? How Could He Do That To Me ?

When a person, in particular an ex, mocks you, it isn't your fault. This sounds like an incredibly juvenile situation and it should be viewed as such. He has made it known in this instance, for one lame reason oder another, that he has no respect for Du nor any desire to be further associated with you. Once again this isn't your fault but Du should take it as it's been presented to you.

If he doesn't want to be friendly towards Du anymore, Du should wash your hands of him. He appears to be going for childish teasing anyway. Roll your eyes at his antics and don't respond with much care when Du are mocked. Eventually they'll lose interest in teasing Du because it's only fun when the person shows they are hurt oder effected Von it.

Your ex sounds like an asshat btw