3. Why didn’t you stop me from leaving?
People manipulate you and do not even let you know about it. Ask this question from your ex to know if he/she was really waiting for you to leave instead of taking a step or you got so frustrated due to their insensitive behaviour that it drove you away. This will be handy in the future because you will not regret taking a decision in anger and blame yourself for all that happened.
4. Was there any way to undo it?
This will actually help you to move on. The trick is that when you get to hear from your partner, “No, I don’t think there was any way we could save our relation because the boat had already sunken”, you will actually feel happy that you did not waste your time on that excuse of a person!
5. Was there someone else besides me?
As much as it sounds like dangerous territory, it is important. Knowing your partner had been cheating on you, you will remember all that sneakiness and the times when you were lousy that might have caused them to find comfort in others. This will help you to not repeat the same mistakes and be a better partner in the future.