How many times have you heard your friends and family members utter, "People are exes for a reason?" This embodies the sentiment that two people who could not make a romantic relationship work have concrete reasons to not be together again. For many, being with your ex may feel like peeling a scab off and rubbing salt on the wound. If you choose to do so, giving a relationship with an ex another chance means you must learn to let go.
Reuniting with your ex means you accept the past and let the baggage go. Don't spend time throwing verbal jabs at your ex in an attempt to make them feel the pain you experienced at prior points in your relationship. If your ex cheated on you or neglected you, when you reunite you are telling them what has happened is left in the past and you are working on the future. Accepting this "second chance", your ex is telling you they want do better in the current relationship.
Constantly comparing yourself to flings or ex-spouses does nothing but tear you down and makes you lose sight of certain issues. This includes acknowledging if your ex wanted to be with another person, then they would not be with you. Your reconciliation time should be focused on the good points of your relationship and why the two of you make a good team. Thinking about other people means you aren't focused on you and your relationship.
A common mistake made by those on the receiving end of a second chance is misinterpreting the kindness of your significant other as a weakness. Wanting to give the relationship another chance doesn't mark a lack of intelligence in the other person. It means is they care enough about you to believe everyone makes mistakes and life is about forgiveness. You don't have to seek absolution, but show the other party that you appreciate this second chance and you value the relationship just as much as they do.
When dating an ex, another saying pops into my head. "Forgive but not forget." There may be things in the relationship you cannot and should not ever forget. Allow your prior maltreatment to always remind you that you deserve better. Don't be a fool when embarking on your second chance and take things slow. It is possible you and the ex are just not meant to be together. Realize that life is too short. Putting aside anger is what will aide in eventually healing your relationship and letting it evolve into what it is meant to be.