Ok, so I had seen the post, but even removing the signals I still couldn't get the model to update when I finished editing, that is why I thought I had to reput the signals. I then realised the problem was that getText() I was returning the QString which did not update, by returning QTextEdit::toPlainText the data is updated.
Furthermore the reason i got the error when adding Q_OBJECT was that I forgot to delete the moc file, after that I didn't get the error anymore.
Thank you for your help