tl;dr My husband's sister died suddenly and unexpectedly at the age of 19.
My husband had a lot of issues with abandonment since his parents were losers (both ended up in prison during his childhood), and he had the mentality that life sucked and you could never be disappointed if you never expected things to go well. We met, he left the hometown he hated, and we started a new life in a really awesome state. We got a cat, bought a new car, he got a really good job, and things were looking good. We got engaged, then we got married, and we were talking about having kids.
That's when his sister started getting severe migraines to the point of hospitalization, and died a few weeks later. She was in perfect health, in a great college program, and had a full life ahead of her. And then suddenly she was gone.
A few weeks went by before my husband had what he referred to as a total mental breakdown. He began having nightmares that I died, and the fear of my death was so overwhelming that he was ready to completely destroy our life together so that he wouldn't suffer it being torn away from him. He would rather take the blame than be the victim.
He said awful things to me to try to push me away. Things like he never loved me, he regrets getting married, he made a mistake moving out here, he's miserable being away from his hometown, etc etc. He would refuse to come home after work, preferring to get blackout drunk with his college-aged coworkers and refuse to call or text me. Sometimes he didn't come home for days, and said just looking at me disgusted him. He kept demanding a divorce, and I had to keep refusing, even as the weeks went on and it got harder and harder to stay with him.
I knew it wasn't really him talking to me like that--grief does awful things. I tried everything I could, but he's incredibly stubborn and was so afraid of this dark alternate universe that he was determined to "let me go," so to speak. He was afraid of me dying, or of him ruining my life somehow. I was so wired with stress that I lost twenty pounds and became severely underweight. I tried being supportive, I tried threats and kicking him out, begging for therapy, all of it.
Eventually my own health was suffering too much, and I made the decision to separate from my husband. He was out partying to bury his pain, refusing to text me back when he would be home, so I packed up every single thing I owned. I even took all the pictures off the walls. I wanted him to come home to an empty house, to a life where I literally vanished, and have him see if that was really what he wanted.
That was a year and a half ago. It took a week of silence before he finally started coming out of his dark hole. It took three more weeks of regular check-ins, therapy, curfews, and strict promises before I moved back into our home. The months that followed sucked because I didn't trust him and he felt absolutely awful. But we kept at it, and eventually the whole thing started to sting less and less. It was awful and so many people got sucked into it, but we got through all the crap. It got better.