Summarize the following:
This is true whether you want to get back together or not. You want to make sure you are both clear about what happened and why. You shouldn’t rush into anything and make a rash decision. Make sure you are somewhere quiet where people won't overhear and make both of you nervous or embarrassed. It is important to forgive and move on when you have a relationship issue. However, if the problems you both had in the relationship haven't gone away, then maybe you two just don't work together as a couple. If you are still upset about something that happened between the two of you and you are not ready to consider getting back together, then be clear about the reason you two broke up before and express any fears you may have about repeating the same situation again. If you have forgiven your ex and you do decide to move forward in the relationship, then it is important to make your expectations known. Otherwise, you may end up in a similar situation. Talk about what you hope will be different this time around and be clear about your feelings.

Summary:
Tell him honestly how you feel. Explain that you broke up the first time for a reason. Discuss expectations for the future.