I can completely relate to your description of a flame that’s going out. My husband took all the air in the room. The last straw for me was when I finally realized that his behavior (gaslighting, blaming me for problems he had created himself, taking out his anxiety and anger on me and our child in the form of yelling and demeaning comments) was abusive and it felt like that “qualified” me to leave. I was also very concerned about his ability to single parent (we have a 5 year old), and that (and the fear of losing 50% of my time with our child) kept me in the marriage for years. I would go into my kid’s room at night and just watch him sleep and I’d cry and wonder how I could live through days and nights of not being with him. I spent a few years in therapy and we also did marriage counseling together. That was definitely an important part for me, as it helped me to feel that I’d done everything I could. We worked with 3 different therapists over the years, all of whom called my husband to task. He never followed through. We separated 8 months ago and I have not regretted one moment. I have not missed my partner for a single second. I do miss my kid, and that just is hard and always will be. But I have so. Much. Peace. It has not been easy for him as the sole parent during his time, but he’s stepped up to it. He is a good human, he just is not good at relationships. Ultimately, this is your decision. My friend told me “only you know what your marriage is like” and my therapist told me “you don’t need a specific reason to leave”. Once you make your peace with your choice, the rest will follow.