Moral of the story..

Do NOT take them back UNTIL or IF they can PROVE to you over time that it will NOT happen again, that they are truly sorry, and what will happen if they DO let it happen again...

Do NOT take them back UNTIL you have fully forgiven them and UNTIL you KNOW that you can move on from it.

Reconciling for the wrong reasons or too soon is a recipe for disaster. Do your homework and make them do their homework.