Well, lemme define what closure is, especially when a girl is talking about it and she says she treated her Ex bad, It basically means that this girl first of all, is not over this dude because she has that inner guilt and the desire to make it right between her and her Ex,this means that she literally misses the way her ex used to love her, treat her right even though she was mean to him and everything and that means, this is haunting her back.So what she basically going to do is, going to re-unite with her Ex so that she can leave a better impression,(basically man, the reality is she is trying to make things better with her Ex in u know, Love kinda way), and this blv me will really be bad on ur side because whatever they had will be re-kindled and you will be out of the picture in no time.Am not saying this to get you worried or anything but this is just the truth and facts of life, so just remember in dat closure, there is still gonna be kissing and cuddling, and maybe lovemaking too(If she loves u alot, she won't do that) but the way am seein da situation, seems like she goin to do it.So all am saying is just embrace yourself and be strong because i don't think you going to like the outcome of that closure, only if you are luck and u made a great impact on her than her Ex did, if u didn;t believe me, its guaranteed that you going to be out of the picture of maybe you'll just have to be sharing her with her Ex.
Good luck son
check this out http://www.sydneytrevion.blogspot.com/, might help u.