So so beyond sorry that you are going through this Lostin. It has been decades since I left my qualifier and I still remember the off the charts, glow-in-the-dark pain. Just treat yourself as well as you can and get through each day to the best of your ability. It really is the most extreme emotional experience.
Relationship closure seems to be a kind of myth to me. I don't know if I ever heard of anyone who has gotten it. Perhaps someone at sometime but probably not when involved with an addict. After the passage of time I found healing and acceptance and quite a different way of looking at myself and reality.
Let us know how you get on. Big hug!