I just saw this question on a TV-Show, and there was really so funny answers.
The question is "what would you want to say to your ex boyfriend's new girlfriend". You don't need to give serious answers :-)
"Sweetheart, ask him how his wife and six kids in Australia are doing!"
"Wish you well~ and Goooood Luck." would be what I would really say and fictionally to add, "I hope you enjoy double standards... especially when you are sick and not feeling well. I hope you enjoy long discertations about their day and ailments but never being asked about how your day was. I also hope you like limited vanilla sex!"