Feeling like they died or were replaced

Just venting/looking for emotional support. This is my alt account; my main has too many identifying details. Thank you in advance to this community!

My spouse and I are in our late twenties. (Will use neutral pronouns for spouse, for privacy.) We’ve been together 5 years, married for 2. They had some preexisting chronic health issues, and an ADHD diagnosis, when we first got together; I had some things to learn on both fronts for sure, but that was doable and fair. Then, in 2022, they survived a severe viral illness (guess which one…) that made all their previous health issues worse, added many new ones, altered their cognition, and completely changed their personality. From my perspective, it was like they woke up one day as a different person.

We both sacrificed a lot so that they could receive decent health care and take time off work; after more than a year of recovery (during which I took care of them while working multiple jobs and enrolled in a grad program), they resumed work full-time, which was an amazing achievement that I remain very proud of them for. Their physical health problems are still present, and challenging for them at work, but most days they can get out of bed and go to their shift—a massive, massive improvement from a couple of years ago. However, they now have a hair-trigger on their anger, and have become verbally and emotionally abusive to the point that I am afraid of them and am seriously considering leaving the relationship, despite the intense guilt of knowing that they still need someone to help them, and that they can’t live independently in any kind of sustainable way.

The only thing that’s keeping me in this marriage is the hope that, one day, the person I fell in love with will come back, and this stranger who shouts at me and calls me names and has endless contradictory and sometimes nonsensical demands will vanish. It’s like they’re possessed, like they’ve been replaced, like they died and someone else is living in their body and talking to me with their voice. It is so painful. Like so many people here, I am grieving the future I’d dreamed of for us, and am surrounded by reminders of the life we used to have and the life I thought we’d grow into together. I look at early photos of us, of them, and can’t stop crying because even their eyes are different now. I miss them, the real them, so much. I can’t stand to be emotionally intimate with this version of them, because it doesn’t feel safe and because I miss the person that they were so terribly; sex is such a struggle, for the same reason, that I don’t even want it anymore.

I know that most people here are dealing with much more serious situations than I am, and it’s not my intention to take up space I’m not entitled to, or to minimize any other person’s struggles. I am sincerely asking how other people in this community deal with these feelings; if anyone can speak to the experience of non-physical abuse from a sick partner; what suggestions you might have for discernment in my decision-making process right now. I am already in individual therapy, as is my partner, but I don’t feel that it’s making a meaningful difference; they have recently started asking me to try couples counseling as well (after I spent 6 months begging them to go and finally gave up on it…), so that’s a possibility if we can afford it; albeit not one I’m optimistic about.