Most Helpful Girl
I think feelings of regret are a result of wondering, 'what if'. What if you stayed together, would your feelings have come back? What if you guys would have been okay even though your feelings for him faded.
I think there's probably also a certain amount of missing the conversation and the relationship, there's probably also a certain amount of missing him too.
When you feel regret, you should remind yourself why you broke up with him. You need to remember why it didn't work out, many times following a relationship's end people look at it through rose tinted glasses and that is why they regret the breakup or want to get back together.