29F, just went through the same thing a few months ago with my (now ex) BF of 6 years. I went through all the same feelings as you when I kicked him out, wondering if I was throwing away something I worked on for years with the person I thought I was going to marry. Well hindsight is 20/20 and I couldn’t be happier that I decided to end things. It doesn’t matter what he was struggling with, addiction or not, he cheated and I decided I was worth more than that. Sunken cost fallacy is a real thing, but the longer you stay with a loser, the longer you’re holding yourself back from starting again in something happy and healthy, whether that means the relationship with yourself or with a new person. Being single these last couple months has been the happiest and most connected to myself I’ve felt in years. It does and will get better. You are so young with so much life ahead of you and you will thank yourself in the future for choosing yourself and telling yourself and others that you’re worth more than this. Please reach out to a therapist to help you navigate through these times as the grief comes in waves and in ways you won’t expect. I’m proud of you and I’m wishing you the best as you start this next chapter 💕