Our Brain are an amazing computer. Most powerful "tool" that exist in the Universe, as we currently know. They store memories, feelings associated with these memories, and our beliefs.
I still dream about my ex gf, who I ended relationship with more than 2 years ago. Sometimes my brain will trie to convience me to contact her again. Things were "so beautiful back then". Everything was lolipops and honey. But, was it really? If that was true, my ex wasn't my ex. We had a great time for a while but I certanly would not have left her, if things were good. So I choose not to contact her. In fact, whenever my brains start to bring up these thoughts, I remember of all the reasons why I quit the relationship. That seems to be enough.
I hope you get the anology.