I know how you feel about the emptiness occasionally. I have been free of my A for over a year now. Every once in awhile something happens and then I go back to all the memories I had and feel sad.
This weekend I had to go back to my old home that he and I shared and I seen all my perennials in the yard and the home I designed.
Then I heard how he does things with his new girlfriend everynight and they are going on vacation. I think why didnt he do those things with me. Why did I come home to someone drunk everynight who passed out early. Those things just go thru my mind and I dont know why. I am happy for him that he is now happy but in another way it hurts.
The good part is that next week at this time I will have forgotten all about it and remember just what a good life I have now. So I think it is normal for everyone to do this. And, just as fast as one of these episodes come on , they leave just as quickly. As time goes by I have noticed these episodes get fewer and farther in between.